Light-emitting device, method for designing light-emitting device, method for driving light-emitting device, illumination method, and method for manufacturing light-emitting device

ABSTRACT

A light-emitting device that can implement a natural, vivid, highly visible and comfortable appearance of colors and appearance of objects as if the objects are seen outdoors is provided. The light-emitting device can change the appearance of colors of the illuminated objects so as to satisfy the requirements for various illuminations. Furthermore, the appearance of colors of the light-emitting device which currently exists or is in use, and which includes a semiconductor light-emitting device of which appearance of colors is not very good, is improved. A method for driving the light-emitting device, an illumination method by the device, and a method for manufacturing the light-emitting device are also provided. These features are achieved by the light-emitting device that incorporates light-emitting elements and satisfies predetermined requirements, in which φ SSL (λ) emitted from the light-emitting device satisfies a predetermined condition.

CROSS-REFERENCE OF RELATED APPLICATION

The present application incorporates, as disclosed content of thedescription thereof, the entire content of the description, Claims,Drawings and Abstract of Japanese Patent Application No. 2013-042268filed on Mar. 4, 2013, the entire content of the description, Claims,Drawings and Abstract of Japanese Patent Application No. 2013-042269filed on Mar. 4, 2013, and a part or all of the content disclosed in thepatent documents or the like cited in the present description.

TECHNICAL FIELD

The present invention relates to a light-emitting device in which aplurality of light emitting areas exists, and more particularly to alight-emitting device that can change the luminous flux amount and/orradiant flux amount emitted from each light emitting area. The presentinvention also relates to a method for designing the light-emittingdevice, a method for driving the light-emitting device, and anillumination method. The present invention also relates to alight-emitting device that incorporates both a light-emitting elementand a control element. The present invention also relates to a methodfor manufacturing and a method for designing a light-emitting device formanufacturing a new light-emitting device by disposing a control elementin a conventional light-emitting device. Furthermore, the presentinvention relates to an illumination method using the light-emittingdevice.

BACKGROUND ART

Recent advances toward higher output and higher efficiency in GaNrelated semiconductor light-emitting elements have been dramatic. Inaddition, active research is underway to increase efficiency ofsemiconductor light-emitting elements and various phosphors that use anelectron beam as an excitation source. As a result, power-savingcapabilities of today's light-emitting devices such as light sources,light source modules including light sources, fixtures including lightsource modules, and systems including fixtures are advancing rapidly ascompared to their conventional counterparts.

For example, it is widely popular to incorporate a GaN related bluelight-emitting element as an excitation light source of a yellowphosphor and create a so-called pseudo-white light source from aspectrum of the GaN related blue light-emitting element and a spectrumof the yellow phosphor, use the pseudo-white light source as anillumination light source or create a lighting fixture that incorporatesthe pseudo-white light source or, further, fabricate a lighting systemin which a plurality of such fixtures are arranged in a space (refer toPatent Document 1).

Among packaged LEDs (for example, those that include the GaN relatedblue light-emitting element, the yellow phosphor, an encapsulant, andthe like in a package material) which are a type of an illuminationlight source that can be incorporated into such modes, there areproducts with luminous efficacy of a source as a packaged LED exceeding150 lm/W in a correlated color temperature (CCT) region of around 6000 K(refer to Non-Patent Document 2).

Furthermore, similar advances toward higher efficiency and greater powersaving are being made in light sources for liquid crystal display (LCD)backlighting and the like.

However, many have pointed out that such light-emitting devices aimingfor higher efficiency do not give sufficient consideration to colorappearance. In particular, when used for illumination purposes, “colorappearance” when illuminating an object with a light-emitting devicesuch as alight source, fixture, system, or the like is particularlyimportant together with increasing efficiency of the light-emittingdevice.

Attempts to address this issue include superimposing a spectrum of a redphosphor or a red semiconductor light-emitting element on a spectrum ofa blue light-emitting element and a spectrum of a yellow phosphor inorder to improve scores of a color rendering index (CRI) (CIE (13.3)) asestablished by the International Commission on Illumination (CommissionInternationale de l'Eclairage/CIE). For example, while an average colorrendering index (R_(a)) and a special color rendering index (R₉) withrespect to a vivid red color sample for a typical spectrum (CCT=around6800 K) that does not include a red source are R_(a)=81 and R₉=24respectively, the scores of the color rendering indices can be improvedto R_(a)=98 and R₉=95 when a red source is included (refer to PatentDocument 2).

In addition, another attempt involves adjusting a spectrum emitted froma light-emitting device particularly for special illuminationapplications so that color appearance of an object is based on a desiredcolor. For example, Non-Patent Document 1 describes a red-basedillumination light source.

CITATION LIST Patent Documents

-   Patent Document 1: Japanese Patent Publication No. 3503139-   Patent Document 2: WO2011/024818

Non-Patent Document

Non-Patent Document 1: “General-purpose fluorescent light meat-kun”,[online], Prince Electric Co., Ltd., [retrieved on May 16, 2011],Internet <URL:http://www.prince-d.co.jp/pdct/docs/pdf/catalog_pdf/fl_nrb_ca2011.pdf>

Non-Patent Document 2: LEDs MAGAZINE, [retrieved on Aug. 22, 2011],Internet <URL: http://www.ledsmagazine.com/news/8/8/2>

SUMMARY OF INVENTION Technical Problem

A color rendering index is an index which indicates how close a colorappearance is, when illuminating with light (test light) of alight-emitting device that is an evaluation object, compared to a colorappearance when illuminating with a “reference light” that is selectedin correspondence with a CCT of the test light. In other words, a colorrendering index is an index indicating fidelity of the light-emittingdevice that is an evaluation object. However, recent studies have madeit increasingly clear that a high average color rendering index (R_(a))or a high special color rendering index (R_(i) (where i ranges from 1 to14 or, in Japan, ranges from 1 to 15 pursuant to JIS) does notnecessarily lead to favorable color perception in a person. In otherwords, there is a problem that the aforementioned methods for improvingcolor rendering index scores do not always achieve favorable colorappearance.

Furthermore, the effect of illuminance of an illuminated object causinga variation in color appearance is not included in various colorrendition metric that are currently in use. It is an everyday experiencethat a vivid color of a flower seen outdoors where illuminance isnormally around 10000 lx or higher becomes dull once the flower isbrought indoors where illuminance is around 500 lx as though the floweritself has changed to a different flower with lower chroma, even thoughthe color is fundamentally the same. Generally, saturation regarding thecolor appearance of an object is dependent on illuminance, andsaturation decreases as illuminance decreases even though a spectralpower distribution that is being illuminated is unchanged. In otherwords, color appearance becomes dull. This effect is known as the Hunteffect.

Despite having a significant effect on color rendering property, asthings stand, the Hunt effect is not actively considered for overallevaluation of a light-emitting device such as a light source, a fixture,or a system. In addition, while the simplest way to compensate for theHunt effect is to dramatically increase indoor illuminance, this causesan unnecessary increase in energy consumption. Furthermore, a specificmethod of achieving a color appearance or an object appearance that isas natural, vivid, highly visible, and comfortable as perceived outdoorsunder illuminance comparable to an indoor illumination environmentremains to be revealed.

Meanwhile, with light having its spectrum adjusted so as to, forexample, increase chroma of red to be used for special illumination inrestaurants or for food illumination, there is a problem that hue(angle) deviation increases in comparison to reference light asevidenced by yellow appearing reddish or blue appearing greenish. Inother words, the color appearance of colors other than a specific colorof an illuminated object becomes unnatural. Another problem is that whena white object is illuminated by such light, the white object itselfappears colored and is no longer perceived as being white.

To solve the above problems, the present inventor reached, as disclosedin Japanese Patent Application No. 2011-223472, an invention of anillumination method and an overall light-emitting device such as anillumination light source, a lighting fixture, and a lighting systemwhich are capable of achieving, under an indoor illumination environmentwhere illuminance is around 5000 lx or lower including cases wheredetailed work is performed and generally around 1500 lx or lower, acolor appearance or an object appearance as perceived by a person whichis as natural, vivid, highly visible, and comfortable as perceivedoutdoors in a high-illuminance environment regardless of scores ofvarious color rendition metric. At the same time, the present inventoralso reached an illumination method that implements a comfortableillumination environment at high efficiency. Further, the presentinventor reached design guidelines for this preferred light-emittingdevice.

The light sources that satisfy the requirements which the presentinventor have already discovered can implement a natural, vivid, highlyvisible, and comfortable appearance of colors and an appearance ofobjects under an indoor luminance environment as if the objects wereseen under an outdoor environment.

However, the concept of an optimum illumination slightly differsdepending on age, gender, country and the like, and also differsdepending on the space and purpose of the illumination. Furthermore,taste in illumination which an individual feels to be optimum may differgreatly depending on the living environment where the individual grew upand the culture thereof.

LED illumination is already common, but many products which do notconsider the appearance of colors are on the market. Many LED lightingfixtures/lighting systems are already in practical use. However even ifa user experiences an unnatural feeling and is unsatisfied with theappearance of colors, it is impractical to replace the target lightingfixtures/systems or the like to improve the appearance of colorsthereof, if time constraints and economic issues of the user areconsidered.

It is an object of the present invention to provide a light-emittingdevice that can implement a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects as if theobjects are seen outdoors, and to provide a light-emitting device thatcan change the appearance of colors of the illuminated objects so as tosatisfy the requirements for various illuminations, and a method fordesigning thereof. Furthermore, it is an object of the present inventionto provide a method for driving the light-emitting device and anillumination method with a device.

The present invention is for improving the appearance of colors of alight-emitting device which currently exists or is in use, and whichincludes a semiconductor light-emitting device of which appearance ofcolors is not very good. Further, the present invention discloses amethod for designing and a method for manufacturing this light-emittingdevice, and also discloses an illumination method using thislight-emitting device.

Moreover, the present invention also discloses a method or the like forfinely adjusting the appearance of colors of a semiconductorlight-emitting device having good appearance of colors according to thetaste of the user using the above mentioned technique.

Solution to Problem

In order to achieve the objects described above, the present inventionincludes first to fifth inventions described below. The first inventionof the present invention relates to the following light-emitting device.The light-emitting device according to the first invention of thepresent invention includes first and second embodiments.

[1]

A light-emitting device incorporating a light-emitting element andsatisfying the following A or B, wherein

φ_(SSL)(λ) emitted from the light-emitting device satisfies both thefollowing Condition 1 and Condition 2:

A: a light-emitting device which includes M number of light emittingareas (M is 2 or greater natural number) and has the light-emittingelements in the light emitting areas, wherein

when φ_(SSL)N(λ) (N is 1 to M) is a spectral power distribution of alight emitted from each light emitting area in a main radiant directionof the light-emitting device, φ_(SSL)(λ), which is a spectral powerdistribution of all the lights emitted from the light-emitting device inthe radiant direction, is

[Expression  1]${\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{{N(\lambda)}.}}}$B: a light-emitting device incorporating the light-emitting element anda control element, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the light-emitting element in a main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the light-emitting device in the main radiantdirection is denoted by φ_(SSL)(λ)

Φ_(elm)(λ) does not satisfy at least one of the following Conditions 1and 2:

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 2]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 3]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2)[2]

The light-emitting device according to [1], satisfying the A.

[3]

The light-emitting device according to [2], wherein

a semiconductor light-emitting element is included in at least one ofthe light emitting areas as the light-emitting element.

[4]

The light-emitting device according to [2] or [3], including lightemitting areas so that φ_(SSL)(λ) can satisfy the Conditions 1 to 2 bychanging a luminous flux amount and/or a radiant flux amount emittedfrom the light emitting areas.

[5]

The light-emitting device according to any one of [2] to [4], wherein

all of φ_(SSL)N(λ) (N is 1 to M) satisfies the Condition 1 and Condition2.

[6] The light-emitting device according to any one of [2] to [5],wherein

at least one light emitting area of the M number of light emitting areashas wiring that allows the light emitting area to be electrically drivenindependently from other light emitting areas.

[7]

The light-emitting device according to [6], wherein

all the M numbers of light emitting areas each have wiring that allowsthe light emitting area to be electrically driven independently fromother light emitting areas.

[8]

The light-emitting device according to any one of [2] to [7], wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus can be changed.

[9]

The light-emitting device according to [8], wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction can be independently controlledwhen at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[10]

The light-emitting device according to any one of [2] to [9], wherein

a maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light emitting areas closest to eachother, is 0.4 mm or more and 200 mm or less.

[11]

The light-emitting device according to any one of [2] to [10], includingthe light emitting areas that allow φ_(SSL)(λ) to further satisfy thefollowing Conditions 3 to 4 by changing a luminous flux amount and/or aradiant flux amount emitted from the light emitting areas:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light emitted in theradiant direction are respectively denoted by a*_(nref) and b*_(nref)(where n is a natural number from 1 to 15), then each saturationdifference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 4} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 5} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[12]

The light-emitting device according to any one of [2] to [11], wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[13]

The light-emitting device according to any one of [2] to [12], wherein

a correlated color temperature T_(SSL) (K) of light emitted from thelight-emitting device in the radiant direction satisfies

2550 (K)≦T_(SSL)(K)≦5650 (K).

[14]

The light-emitting device according to [1], satisfying the B.

[15]

The light-emitting device according to [14], wherein

the light-emitting element includes a semiconductor light-emittingelement.

[16]

The light-emitting device according to [14] or [15], wherein

Φ_(elm)(λ) does not satisfy at least one of the following Condition 3and Condition 4, and φ_(SSL)(λ) satisfies both the following Condition 3and Condition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 6} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 7} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8<|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−29 {(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

[17]

A light-emitting device incorporating a light-emitting element includinga semiconductor light-emitting element, and a control element, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the light-emitting element in a main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the light-emitting device in the main radiantdirection is denoted by φ_(SSL)(λ),

Φ_(elm)(λ) satisfies both of the following Condition 1 and Condition 2,and φ_(SSL)(λ) also satisfies both of the following Conditions 1 and 2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 8]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 9]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2)[18]

The light-emitting device according to [17], wherein

Φ_(elm)(λ) satisfies both of the following Condition 3 and Condition 4,and φ_(SSL)(λ) also satisfies both of the following Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 10} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 11} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

[19]

The light-emitting device according to [14], [15] or [17], wherein

if D_(uv) derived from the spectral power distribution of the lightemitted from the light-emitting element in the main radiant direction isdenoted by D_(uv) (Φ_(elm)) and D_(uv) derived from the spectral powerdistribution of the light emitted from the light-emitting device in themain radiant direction is denoted by D_(uv) (φ_(SSL))

D_(uv) (Φ_(SSL))<D_(uv) (Φ_(elm)) is satisfied.

[20]

The light-emitting device according to [14], [15] or [17], wherein

if A_(cg) derived from the spectral power distribution of the lightemitted from the light-emitting element in the main radiant direction isdenoted by A_(cg) (Φ_(elm)), and A_(cg) derived from the spectral powerdistribution of the light emitted from the light-emitting device in themain radiant direction is denoted by A_(cg) (φ_(SSL)),

A_(cg) (φ_(SSL))<A_(cg) (Φ_(elm)) is satisfied.

[21] The light-emitting device according to [16] or [18], wherein

if an average of the saturation difference derived from the spectralpower distribution of the light emitted from the light-emitting elementin the main radiant direction is denoted by SAT_(av) (Φ_(elm)), and

if an average of the saturation difference derived from the spectralpower distribution of the light emitted from the light-emitting devicein the main radiant direction is denoted by SAT_(av) (φ_(SSL)),

SAT_(av) (Φ_(elm))<SAT_(av) (φ_(SSL)) is satisfied.

[22]

The light-emitting device according to any one of [14] to [21], wherein

the control element is an optical filter that absorbs or reflects lightin a range of 380 nm≦λ(nm)≦780 nm.

[23]

The light-emitting device according to any one of [14] to [22], wherein

the control element has a collection function and/or a diffusionfunction of the light emitted from the light-emitting element.

[24]

The light-emitting device according to [23], wherein

the collection function and/or the diffusion function of the controlelement is implemented by at least one of the functions of a concavelens, a convex lens and a Fresnel lens.

[25]

The light-emitting device according to any one of [14] to [24], wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[26]

The light-emitting device according to [16] or [18], wherein theabsolute value of each difference in hue angles |Δh_(n)| light-emittingdevice satisfies

0.0003≦|Δh_(n)| 8.3 (degree) (where n is a natural number from 1 to 15).

[27]

The light-emitting device according to [16] or [18], wherein

the average SAT_(av) of the saturation difference of the light-emittingdevice represented by the Formula (3) satisfies the following Formula(4)′

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 12} \rbrack & \; \\{1.2 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq {6.3.}} & (4)^{\prime}\end{matrix}$[28]

The light-emitting device according to [16] or [18], wherein

the each saturation difference ΔC_(n) of the light-emitting devicesatisfies

−3.4≦ΔC_(n)≦16.8 (where n is a natural number from 1 to 15).

[29]

The light-emitting device according to [16] or [18], wherein

the difference |ΔC_(max)−ΔC_(min)| between the maximum saturationdifference value of the light-emitting device and the minimum saturationdifference value thereof, satisfies3.2≦|ΔC _(max) −ΔC _(min)|≦17.8.[30]

The light-emitting device according to any one of [14] to [29], wherein

the light emitted from the light-emitting device in the radiantdirection has the distance D_(uv) from the black-body radiation locusthat specifies−0.0250≦D _(uv)≦−0.0100.[31]

The light-emitting device according to any one of [14] to [30], wherein

the index A_(cg) of the light-emitting device represented by the Formula(1) or (2) satisfies−322≦A _(cg)≦−12.[32]

The light-emitting device according to any one of [14] to [31], wherein

the luminous efficacy of radiation K (lm/W) in a wavelength range from380 nm to 780 nm as derived from the spectral power distribution φ_(SSL)(λ) of light emitted from the light-emitting device in the radiantdirection satisfies206(lm/W)≦K(lm/W)≦288(lm/W).[33]

The light-emitting device according to any one of [14] to [32], wherein

the correlated color temperature T(K) of the light-emitting devicesatisfies2550(K)≦T(K)≦5650(K).[34]

The light-emitting device according to any one of [14] to [33], wherein

illuminance at which the light emitted from the light-emitting device inthe radiant direction illuminates objects is 150 lx to 5000 lx.

[35]

The light-emitting device according to any one of [14] to [34], wherein

the light-emitting device emits, in the radiant direction, light emittedfrom one to six light-emitting elements.

[36]

The light-emitting device according to any one of [14] to [35], wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 380 nm or longer and shorter than 495 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 45 nm.

[37]

The light-emitting device according to [36], wherein the peak wavelengthof the emission spectrum of the semiconductor light-emitting element is395 nm or longer and shorter than 420 nm.

[38]

The light-emitting device according to [36], wherein the peak wavelengthof the emission spectrum of the semiconductor light-emitting element is420 nm or longer and shorter than 455 nm.

[39]

The light-emitting device according to [36], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 455 nm or longer and shorter than 485 nm.

[40]

The light-emitting device according to any one of [14] to [35], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 495 nm or longer and shorter than 590 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 75 nm.

[41]

The light-emitting device according to any one of [14] to [35], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 590 nm or longer and shorter than 780 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 30 nm.

[42]

The light-emitting device according to any one of [14] to [35], wherein

the semiconductor light-emitting element is fabricated on any substrateselected from the group consisting of a sapphire substrate, a GaNsubstrate, a GaAs substrate and a GaP substrate.

[43]

The light-emitting device according to any one of [14] to [35], wherein

the semiconductor light-emitting element is fabricated on a GaNsubstrate or a GaP substrate and a thickness of the substrate is 100 μmto 2 mm.

[44]

The light-emitting device according to any one of [14] to [36], wherein

the semiconductor light-emitting element is fabricated on a sapphiresubstrate or a GaAs substrate and the semiconductor light-emittingelement is removed from the substrate.

[45]

The light-emitting device according to any one of [14] to [39],comprising a phosphor as a light-emitting element.

[46]

The light-emitting device according to [45], wherein

the phosphor includes one to five types of phosphors each havingdifferent emission spectra.

[47]

The light-emitting device according to [45] or [46], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 380 nmor longer and shorter than 495 nm and a full-width at half-maximum of 2nm to 90 nm.

[48]

The light-emitting device according to [47], wherein

the phosphor includes one or more types of phosphors selected from thegroup consisting of a phosphor represented by general formula (5) below,a phosphor represented by general formula (5)′ below, (Sr,Ba)₃MgSi₂O₈:Eu²⁺, and (Ba, Sr, Ca, Mg)Si₂O₂N₂:Eu(Ba,Sr,Ca)MgAl₁₀O₁₇:Mn,Eu  (5)Sr_(a)Ba_(b)Eu_(x)(PO₄)_(c)X_(d)  (5)′(in the general formula (5)′, X is Cl, in addition, c, d, and x arenumbers satisfying 2.7≦c≦3.3, 0.9≦d≦1.1, and 0.3≦x≦1.2, moreover, a andb satisfy conditions represented by a+b=5−x and 0≦b/(a+b)≦0.6).[49]

The light-emitting device according to [45] of [46], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 495 nmor longer and shorter than 590 nm and a full-width at half-maximum of 2to 130 nm.

[50]

The light-emitting device according to [49], wherein the phosphorincludes one or more types of phosphors selected from the groupconsisting of Si_(6−z)Al_(z)O_(z)N_(8−z):Eu (where 0<z<4.2), a phosphorrepresented by general formula (6) below, a phosphor represented bygeneral formula (6)′ below, and SrGaS₄:Eu²⁺Ba_(a)Ca_(b)Sr_(c)Mg_(d)Eu_(x)SiO₄  (6)(in the general formula (6), a, b, c, d, and x satisfy a+b+c+d+x=2,1.0≦a≦2.0, 0≦b≦0.2, 0.2≦c≦1.0, 0≦d<0.2, and 0<x≦0.5).Ba_(1−x−y)Sr_(x)Eu_(y)Mg_(1−z)Mn_(z)Al₁₀O₁₇  (6)′(in the general formula (6)′, x, y, and z respectively satisfy0.1≦x≦0.4, 0.25≦y≦0.6, and 0.05≦z≦0.5).[51]

The light-emitting device according to [45] or [46], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 590 nmor longer and shorter than 780 nm and a full-width at half-maximum of 2nm to 130 nm.

[52]

The light-emitting device according to [51], wherein

the phosphor includes one or more types of phosphors selected from thegroup consisting of a phosphor represented by general formula (7) below,a phosphor represented by general formula (7)′ below, (Sr, Ca,Ba)₂Al_(x)Si_(5−x)O_(x)N_(8−x):Eu (where 0≦x≦2), Eu_(y)(Sr, Ca,Ba)_(1−y):Al_(1+x)Si_(4−x)O_(x)N_(7−x) (where 0≦x<4, 0≦y<0.2),K₂SiF₆:Mn⁴⁺, A_(2+x)M_(y)Mn_(z)F_(n) (where A is Na and/or K; M is Siand Al; −1≦x≦1 and 0.9≦y+z≦1.1 and 0.001≦z≦0.4 and 5≦n≦7), (Ca, Sr, Ba,Mg)AlSiN₃:Eu and/or (Ca, Sr, Ba)AlSiN₃:Eu, and(CaAlSiN₃)_(1−x)(Si₂N₂O)_(x):Eu (where x satisfies 0<x<0.5)(La_(1−x−y)Eu_(x)Ln_(y))₂O₂S  (7)(in the general formula (7), x and y denote numbers respectivelysatisfying 0.02≦x≦0.50 and 0≦y≦0.50, and Ln denotes at least onetrivalent rare-earth element among Y, Gd, Lu, Sc, Sm, and Er)(k−x)MgO.xAF₂.GeO₂ :yMn⁴⁺  (7)′(in the general formula (7)′, k, x, and y denote numbers respectivelysatisfying 2.8≦k≦5, 0.1≦x≦0.7, and 0.005≦y≦0.015, and A is calcium (Ca),strontium (Sr), barium (Ba), zinc (Zn), or a mixture consisting of theseelements).[53]

The light-emitting device according to any one of [14] to [35], furthercomprising a phosphor as the light-emitting element, wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 395 nm or longer and shorter than 420 nm, andthe phosphor includes SBCA, β-SiAlON, and CASON.

[54]

The light-emitting device according to any one of [14] to [35], furthercomprising a phosphor as the light-emitting element, wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 395 nm or longer and shorter than 420 nm, andthe phosphor includes SCA, β-SiAlON, and CASON.

[55]

The light-emitting device according to any one of [1] to [54], which isselected from the group consisting of a packaged LED, an LED module, anLED lighting fixture, and an LED lighting system.

[56]

The light-emitting device according to any one of [1] to [55], which isused as one selected from the group consisting of a residential uses'device, an exhibition illumination device, a presentation illuminationdevice, a medical illumination device, a work illumination device, anillumination device incorporated in industrial equipments, anillumination device for interior of transportation, an illuminationdevice for works of art, and an illumination device for aged persons.

In order to achieve the objects described above, the second invention ofthe present invention relates to the following method for designing alight-emitting device. The method for designing a light-emitting deviceaccording to the second invention of the present invention includesfirst and second embodiments.

[57]

A method for designing a light-emitting device which includes M numberof light emitting areas (M is 2 or greater natural number), andincorporating a semiconductor light-emitting element as a light-emittingelement in at least one of the light emitting areas,

the method comprising designing the light emitting areas such that, whenφ_(SSL)(λ) (N is 1 to M) is a spectral power distribution of a lightemitted from each light emitting area in a main radiant direction of thelight-emitting device, and φ_(SSL)(λ), which is a spectral powerdistribution of all the lights emitted from the light-emitting device inthe radiant direction, is represented by

[Expression  13]${{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}{\phi_{SSL}{N(\lambda)}}}},$

φ_(SSL)(λ) satisfies the following Conditions 1 to 2 by changing aluminous flux amount and/or a radiant flux amount emitted from the lightemitting areas:

Condition 1:

-   -   light emitted from the light-emitting device includes, in the        main radiant direction thereof, light whose distance D_(uvSSL)        from a black-body radiation locus as defined by ANSI C78.377        satisfies −0.0350≦D_(uvSSL)≦−0.0040,        Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)) andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 14]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 15]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2)[58]

The method for designing a light-emitting device according to [57],wherein

all of φ_(SSL)N(λ) (N is 1 to M) satisfies the Condition 1 and Condition2.

[59]

The method for designing a light-emitting device according to [57] or[58], wherein

at least one light emitting area of the M number of light emitting areashas wiring that allows the light emitting area to be electrically drivenindependently from other light emitting areas.

[60]

The method for designing a light-emitting device according to [59],wherein

all the M numbers of light emitting areas each have wiring that allowsthe light emitting area to be electrically driven independently fromother light emitting areas.

[61]

The method for designing a light-emitting device according to any one of[57] to [60], wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus can be changed.

[62]

The method for designing a light-emitting device according to [61],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction can be independently controlledwhen at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[63]

The method for designing a light-emitting device according to any one of[57] to [62], wherein

a maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light emitting areas closest to eachother, is 0.4 mm or more and 200 mm or less.

[64]

The method for designing a light-emitting device according to any one of[57] to [63],

further comprising allowing φ_(SSL)(λ) to further satisfy the followingConditions 3 to 4 by changing a luminous flux amount and/or a radiantflux amount emitted from the light emitting areas:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC≦18.6 (where n is a natural number from 1 to 15),

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 16} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 17} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min) then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8<|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[65]

The method for designing a light-emitting device according to any one of[57] to [64], wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[66]

The method for designing a light-emitting device according to any one of[57] to [65], wherein

the correlated color temperature T_(SSL) (K) of light emitted from thelight-emitting device in the radiant direction satisfies2550(K)≦T _(SSL)(K)≦5650(K).

In order to achieve the objects described above, the third invention ofthe present invention relates to the following method for driving alight-emitting device.

[67]

A method for driving a light-emitting device which includes M number oflight emitting areas (M is 2 or greater natural number), and has asemiconductor light-emitting element as a light-emitting element in atleast one of the light emitting areas,

the method comprising supplying power to each light emitting area suchthat, when φ_(SSL)(λ) (N is 1 to M) is a spectral power distribution ofa light emitted from each light emitting area in a main radiantdirection of the light-emitting device, and φ_(SSL)(λ), which is aspectral power distribution of all the lights emitted from thelight-emitting device in the radiant direction, is represented by

[Expression  18]${{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}{\phi_{SSL}{N(\lambda)}}}},$

φ_(SSL)(λ) satisfies the following Conditions 1 to 2:

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),[Expression 19]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 20]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[68]

The method for driving a light-emitting device according to [67],wherein

power is supplied to the light emitting areas so that all of φ_(SSL)N(λ)(N is 1 to M) satisfies the Condition 1 and Condition 2.

[69]

The method for driving a light-emitting device according to [67] or[68], wherein

at least one light emitting area of the M number of light emitting areasis electrically driven independently from other light emitting areas.

[70]

The method for driving a light-emitting device according to any one of[67] to [69], wherein

all the M number of light emitting areas are electrically drivenindependently from other light emitting areas.

[71]

The method for driving a light-emitting device according to any one of[67] to [69], wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[72]

The method for driving a light-emitting device according to [71],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is unchanged when at least oneselected from the group consisting of the index A_(cg) represented bythe Formula (1) or (2), the correlated color temperature T_(SSL)(K) andthe distance D_(uvSSL) from the black-body radiation locus is changed.

[73]

The method for driving a light-emitting device according to [71],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is decreased when the index A_(cg)represented by the Formula (1) or (2) is decreased.

[74]

The method for driving a light-emitting device according to [71],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is increased when the correlatedcolor temperature T_(SSL)(K) is increased.

[75]

The method for driving a light-emitting device according to [71],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is decreased when the distanceD_(uvSSL) from the black-body radiation locus is decreased.

[76]

The method for driving a light-emitting device according to any one of[67] to [75],

further comprising supplying power such that φ_(SSL)(λ) furthersatisfies the following Condition 3 and Condition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light emitted in theradiant direction are respectively denoted by a*_(nref) and b*_(nref)(where n is a natural number from 1 to 15), then each saturationdifference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15),

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 21} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 22} \rbrack & \; \\{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

In order to achieve the objects described above, the fourth invention ofthe present invention relates to the following illumination method. Theillumination method according to the fourth invention of the presentinvention includes first and second embodiments.

[77]

An illumination method comprising:

illuminated objects preparation step of preparing illuminated objects;and

an illumination step of illuminating the objects by light emitted from alight-emitting devices which includes M number of light emitting areas(M is 2 or greater natural number), and has a semiconductorlight-emitting element as a light-emitting element in at least one ofthe light emitting areas,

in the illumination step, when light emitted from the light-emittingdevices illuminate the objects, the objects are illuminated so that thelight measured at a position of the objects satisfies <1>, <2> and <3>below:

<1> a distance D_(uvSSL) from a black-body radiation locus as defined byANSI C78.377 of the light measured at the position of the objectssatisfies −0.0350≦D_(uvSSL)≦−0.0040;

<2> if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light measured at theposition of the objects are respectively denoted by a*_(nSSL) andb*_(nSSL) (where n is a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light measured at theposition of the objects are respectively denoted by a*_(nref) andb*_(nref) (where n is a natural number from 1 to 15), then eachsaturation difference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 23} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 24} \rbrack & \; \\{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

<3> if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light measured at the position of the objects are denoted byθ_(nSSL) (degrees) (where n is a natural number from 1 to 15), and

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light measured at the position of theobjects are denoted by θ_(nref) (degrees) (where n is a natural numberfrom 1 to 15), then an absolute value of each difference in hue angles|Δh_(n)| satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

here Δh_(n)=θ_(nSSL)−θ_(nref).

[78]

The illumination method according to [77], wherein

when φ_(SSL)N(λ) (N is 1 to M) is a spectral power distribution of alight which has been emitted from each light-emitting element and hasreached the position of the objects, and φ_(SSL)(λ) is a spectral powerdistribution of the light measured at the position of the objects isrepresented by

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 25} \rbrack & \; \\{{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{N(\lambda)}}}},} & \;\end{matrix}$

all the φ_(SSL)N(λ) (N is 1 to M) can satisfy the <1>, <2> and <3>.

[79]

The illumination method according to [77] or [78], wherein

at least one light emitting area of the M number of light emitting areasis electrically driven independently from other light emitting areas forperforming the illumination.

[80]

The illumination method according to [79], wherein

all the M number of light emitting areas are electrically drivenindependently from other light emitting areas.

[81]

The illumination method according to any one of [77] to [80], wherein

at least one selected from the group consisting of an average saturationdifference represented by the formula (3),

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 26} \rbrack \\{\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},}\end{matrix}$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[82]

The illumination method according to [81], wherein

the luminance in the object is independently controlled when at leastone selected from the group of an average saturation differencerepresented by the formula (3,

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 27} \rbrack \\{\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},}\end{matrix}$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[83]

The illumination method according to [82], wherein

the luminance in the object is unchangeable when at least one selectedfrom the group of an average saturation difference represented by theformula (3),

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 28} \rbrack \\{\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},}\end{matrix}$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[84]

The illumination method according to [82], wherein

the luminance in the object is decreased when the average saturationdifference represented by the formula (3),

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 29} \rbrack \\{\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},}\end{matrix}$is increased.[85]

The illumination method according to [82], wherein

the illuminance in the object is increased when the correlated colortemplate T_(SSL)(K) is increased.

[86]

The illumination method according to [82], wherein

the luminance in the object is decreased when the distance D_(uvSSL)from the black-body radiation locus is decreased.

[87]

The illumination method according to any one of [77] to [86], wherein

if a maximum distance between two arbitrary points on a virtual outerperiphery enveloping the entire light emitting areas closest to eachother is denoted by L, and a distance between the light-emitting deviceand the illumination object is denoted by H,

the distance H is set so as to satisfy5×L≦H≦500×L.

In order to achieve the objects described above, the fifth invention ofthe present invention relates to the following method for manufacturinga light-emitting device.

[88]

A method for manufacturing a light-emitting device: incorporating alight-emitting element which includes a semiconductor light-emittingelement; and a control element, the method comprising:

a step of preparing a first light-emitting device having thelight-emitting element; and

a step of manufacturing a second light-emitting device by disposing thecontrol element so as to act on at least a part of light emitted fromthe first light-emitting device in a main radiant direction, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the first light-emitting device in the main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the second light-emitting device in the mainradiant direction is denoted by φ_(SSL)(λ),

Φ_(elm)(λ) does not satisfy at least one of the following Condition 1and Condition 2, and φ_(SSL)(λ) satisfies both the Condition 1 andCondition 2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 30]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 31]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[89]

The method for manufacturing a light-emitting device according to [88],wherein

Φ_(elm)(λ) does not satisfy at least one of the following Condition 3and Condition 4, and φ_(SSL)(λ) satisfies both the Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 32} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 33} \rbrack & \; \\{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

[90]

A method for manufacturing a light-emitting device incorporating: alight-emitting element which includes a semiconductor light-emittingelement; and a control element, the method comprising:

a step of preparing a first light-emitting device having thelight-emitting element; and

a step of manufacturing a second light-emitting device by disposing thecontrol element so as to act on at least a part of light emitted fromthe first light-emitting device in a main radiant direction, wherein

if a wavelength is denoted by λ (nm), a spectral power distribution of alight emitted from the first light-emitting device in the main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the second light-emitting device in the mainradiant direction is denoted by φ_(SSL)(λ)

Φ_(elm)(λ) satisfies both the following Condition 1 and Condition 2, andφ_(SSL)(λ) also satisfies both the following Condition 1 and Condition2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included; Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of 4,[Expression 34]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 35]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[91]

The method for manufacturing a light-emitting device according to [90],wherein

Φ_(elm)(λ) satisfies both of the following Condition 3 and Condition 4,and φ_(SSL)(λ) also satisfies both of the following Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 36} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 37} \rbrack & \; \\{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6.where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

Advantageous Effects of Invention

According to the first and fifth invention of the present invention,compared to a case where illumination is performed with reference light(sometimes referred to as experimental reference light), a case whereillumination is performed by a light-emitting device emitting lightwhich produces a color appearance close to reference light and which hasa high R_(a) and a high R_(i) (sometimes referred to as experimentalpseudo-reference light), and the like, a light-emitting device and anillumination method that can implement a truly good appearance of colorsof object, which are judged by subjects to be more favorable, areachieved even at an approximately similar CCT and/or an approximatelysimilar illuminance. Furthermore, according to the second embodiment ofthe first and fourth invention of the present invention, the appearanceof colors of a light-emitting device, which currently exists or is inuse, and which includes a semiconductor light-emitting device of whichappearance of colors is not very good, can be improved to the goodappearance of colors mentioned above. Furthermore, according to thepresent invention, the appearance of colors of the semiconductorlight-emitting device, which excels in the appearance of colors, can befurther adjusted according to the taste of the user using a similartechnique.

Particularly in the first to fifth inventions of the present invention,a natural, vivid, highly visible and comfortable appearance of colorsand appearance of objects as if the objects are seen outdoors can beimplemented, and according to the first embodiment of the first tofourth inventions of the present invention, the chromaticity points(that is, the correlated color temperature and distance D_(uv) from theblack-body radiation locus as defined by ANSI C78.377) of the lightsource can be changed according to the illuminated space and purpose ofuse. Further, by changing A_(cg), which greatly influences theappearance of colors, the saturation (chroma) of the illumination objectilluminated by this light-emitting device can also be changed. Moreover,by making the luminance of the luminous flux and/or the radiant flux ofthe light source or the illumination object variable with respect to thechange of the chromaticity points of the light source, the luminancewith respect to the chroma (saturation), correlated color temperature,D_(uv), etc. of an illumination object can be controlled to the optimum.

Advantageous effects achieved by the first to fifth inventions of thepresent invention can be more specifically exemplified regarding colorappearance of an object as follows.

First, when illuminating by a light-emitting device according to thefirst invention of the present invention such as a light source, afixture, or a system or illuminating with the illumination methodaccording to the fourth invention of the present invention, compared tocases where illumination is performed with experimental reference lightor experimental pseudo-reference light, white appears whiter, morenatural, and more comfortable even at an approximately similar CCTand/or an approximately similar illuminance. Furthermore, differences inlightness among achromatic colors such as white, gray, and black becomemore visible. As a result, for example, black letters or the like on anordinary sheet of white paper become more legible. Moreover, whiledetails will be given later, such an effect is completely unexpected inthe context of conventional wisdom.

Second, with illuminance that is realized by a light-emitting deviceaccording to the first invention of the present invention or illuminancewhen illuminating with the illumination method according to the fourthinvention of the present invention, a truly natural color appearance asthough viewed under several tens of thousands of lx such as underoutdoor illuminance on a sunny day is achieved for a majority of colorssuch as purple, bluish purple, blue, greenish blue, green, yellowishgreen, yellow, reddish yellow, red, and reddish purple, and in somecases, all colors even in an ordinary indoor environment of aroundseveral thousand 1× to several hundred 1×. In addition, the skin colorsof subjects (Japanese), various foods, clothing, wooden colors, and thelike which have intermediate chroma also acquire a natural colorappearance which many of the subjects feel more favorable.

Third, when illuminating by a light-emitting device according to thefirst invention of the present invention or illuminating with theillumination method according to the fourth invention of the presentinvention, colors among close hues can be identified more easily andwork or the like can be performed as comfortably as though under ahigh-illuminance environment as compared to cases where illumination isperformed with experimental reference light or experimentalpseudo-reference light even at an approximately similar CCT and/or anapproximately similar illuminance. Furthermore, specifically, forexample, a plurality of lipsticks with similar red colors can be morereadily distinguished from each other.

Fourth, when illuminating by a light source, a fixture, or a systemaccording to the first invention of the present invention orilluminating with the illumination method according to the fourthinvention of the present invention, objects can be viewed more clearlyand readily as though viewed under a high-illuminance environment ascompared to cases where illumination is performed with experimentalreference light or experimental pseudo-reference light even at anapproximately similar CCT and/or an approximately similar illuminance.

In addition to these effects, in the second embodiment of the first,second, fourth and fifth inventions of the present invention, theappearance of colors can be further adjusted in accordance with thetaste of the user, even in a semiconductor light-emitting device whichexcels in the appearance of colors when used for illumination purposes.

The conveniences implemented by the first embodiment of the first tofourth inventions of the present invention follow.

In other words, optimum illumination differs depending on age, gender,country and the like, or depending on the space and the purpose ofillumination, but if the light-emitting device according to the firstembodiment of the first invention of the present invention, or themethod for driving the light-emitting device according to the firstembodiment of the third invention of the present invention is used, moresuitable illumination conditions can be easily selected from a variablerange.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light;

FIG. 2 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 475 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light;

FIG. 3 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 425 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light;

FIG. 4 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0000);

FIG. 5 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0100);

FIG. 6 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0150);

FIG. 7 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0100);

FIG. 8 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0200);

FIG. 9 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0300);

FIG. 10 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0400);

FIG. 11 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 459 nmand which comprises a green phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0500);

FIG. 12 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0000);

FIG. 13 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0100);

FIG. 14 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0200);

FIG. 15 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0300);

FIG. 16 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=0.0400);

FIG. 17 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0100);

FIG. 18 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0200);

FIG. 19 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0300);

FIG. 20 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0400);

FIG. 21 is a diagram showing a spectral power distribution when assumingthat light emitted from a packaged LED which incorporates foursemiconductor light-emitting elements illuminates the 15 Munsellrenotation color samples, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0500);

FIG. 22 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0001);

FIG. 23 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0100);

FIG. 24 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0194);

FIG. 25 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0303);

FIG. 26 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0401);

FIG. 27 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=0.0496);

FIG. 28 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=−0.0100);

FIG. 29 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=−0.0200);

FIG. 30 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=−0.0303);

FIG. 31 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor, a green phosphor, and a redphosphor, illuminates the 15 Munsell renotation color samples, and aCIELAB color space on which are respectively plotted a* values and b*values of the 15 Munsell renotation color samples when illuminated bythe LED and when illuminated by reference light (Duv=−0.0403);

FIG. 32 is a diagram showing a spectral power distribution when assumingthat light, emitted from a packaged LED which incorporates asemiconductor light-emitting element with a peak wavelength of 405 nmand which comprises a blue phosphor and a red phosphor, illuminates the15 Munsell renotation color samples, and a CIELAB color space on whichare respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when illuminated by the LED and whenilluminated by reference light (Duv=−0.0448);

FIG. 33 is a diagram showing an integral range for a parameter A_(cg)(when a CCT is 5000 K or higher);

FIG. 34 is a diagram showing an integral range of the parameter A_(cg)(when a CCT is lower than 5000 K);

FIG. 35 is a diagram showing a normalized test light spectral powerdistribution (solid line) of test light 5 and a normalized referencelight spectral power distribution (dotted line) of calculationalreference light corresponding to the test light 5;

FIG. 36 is a diagram showing a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the test light 5 and a case where theobject is illuminated by calculational reference light corresponding tothe test light 5;

FIG. 37 is a diagram showing a normalized test light spectral powerdistribution (solid line) of test light 15 and a normalized referencelight spectral power distribution (dotted line) of calculationalreference light corresponding to the test light 15;

FIG. 38 is a diagram showing a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the test light 15 and a case where theobject is illuminated by calculational reference light corresponding tothe test light 15;

FIG. 39 is a diagram showing a normalized test light spectral powerdistribution (solid line) of test light 19 and a normalized referencelight spectral power distribution (dotted line) of calculationalreference light corresponding to the test light 19;

FIG. 40 is a diagram showing a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the test light 19 and a case where theobject is illuminated by calculational reference light corresponding tothe test light 19;

FIG. 41 is a diagram showing a normalized test light spectral powerdistribution (solid line) of comparative test light 14 and a normalizedreference light spectral power distribution (dotted line) ofcalculational reference light corresponding to the comparative testlight 14; and

FIG. 42 is a diagram showing a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the comparative test light 14 and acase where the object is illuminated by calculational reference lightcorresponding to the comparative test light 14.

FIG. 43 is a diagram showing a disposition of light emitting areas ofthe packaged LED used for Example 1;

FIG. 44 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Example 1, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 45 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Example 1, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 46 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Example 1, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 47 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Example 1, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 48 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Example 1, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 49 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 1 are indicated. Thetwo-dot chain line in FIG. 49 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 50 is a diagram showing a disposition of light emitting areas ofthe packaged LED used for Example 2;

FIG. 51 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Example 2, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 52 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Example 2, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 53 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Example 2, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 54 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Example 2, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 55 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Example 2, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 56 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 2 are indicated. Thetwo-dot chain line in FIG. 56 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 57 is a diagram showing a disposition of the light emitting areasof the illumination system used for Example 3;

FIG. 58 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Example 3, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 59 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Example 3, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 60 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Example 3, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 61 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Example 3, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 62 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Example 3, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 63 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 3 are indicated. Thetwo-dot chain line in FIG. 63 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 64 is a diagram showing the deposition of the light emitting areasof the light-emitting device (pair of packaged LEDs) used for Example 4;

FIG. 65 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 9:0 in Example 4, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 66 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 6:3 in Example 4, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 67 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 4.5:4.5 in Example 4, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 68 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:8 in Example 4, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 69 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:9 in Example 4, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 70 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 4 are indicated. Thetwo-dot chain line in FIG. 70 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 71 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Comparative Example 1, and a CIELAB color space onwhich are respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 72 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Comparative Example 1, and a CIELAB color space onwhich are respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 73 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Comparative Example 1, and a CIELAB color space onwhich are respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 74 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Comparative Example 1, and a CIELAB color space onwhich are respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 75 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Comparative Example 1, and a CIELAB color space onwhich are respectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 76 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Comparative Example 1 areindicated. The two-dot chain line in FIG. 76 is a range of D_(uv) thatsatisfies Condition 1 of the first embodiment of the first to fourthinventions of the present invention;

FIG. 77 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Example 5, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 78 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Example 5, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 79 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Example 5, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 80 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Example 5, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 81 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Example 5, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 82 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 5 are indicated. Thetwo-dot chain line in FIG. 82 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 83 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 3:0 in Example 6, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 84 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2:1 in Example 6, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 85 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1.5:1.5 in Example 6, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 86 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:2 in Example 6, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 87 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:3 in Example 6, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 88 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 6 are indicated. Thetwo-dot chain line in FIG. 88 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 89 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 5:0 in Example 7, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint A);

FIG. 90 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 4:1 in Example 7, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint B);

FIG. 91 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 2.5:2.5 in Example 7, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint C);

FIG. 92 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 1:4 in Example 7, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint D);

FIG. 93 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is 0:5 in Example 7, and a CIELAB color space on which arerespectively plotted a* values and b* values of the 15 Munsellrenotation color samples when respectively assuming a case (solid line)where an object is illuminated by the spectral power distribution and acase (dotted line) where an object is illuminated by calculationalreference light corresponding to the spectral power distribution (drivepoint E);

FIG. 94 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 7 are indicated. Thetwo-dot chain line in FIG. 94 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 95 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1, the light emitting area2 and the light emitting area 3 is 3:0:0 in Example 8, and a CIELABcolor space on which are respectively plotted a* values and b* values ofthe 15 Munsell renotation color samples when respectively assuming acase (solid line) where an object is illuminated by the spectral powerdistribution and a case (dotted line) where an object is illuminated bycalculational reference light corresponding to the spectral powerdistribution (drive point A);

FIG. 96 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1, the light emitting area2 and the light emitting area 3 is 0:3:0 in Example 8, and a CIELABcolor space on which are respectively plotted a* values and b* values ofthe 15 Munsell renotation color samples when respectively assuming acase (solid line) where an object is illuminated by the spectral powerdistribution and a case (dotted line) where an object is illuminated bycalculational reference light corresponding to the spectral powerdistribution (drive point B);

FIG. 97 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1, the light emitting area2 and the light emitting area 3 is 0:0:3 in Example 8, and a CIELABcolor space on which are respectively plotted a* values and b* values ofthe 15 Munsell renotation color samples when respectively assuming acase (solid line) where an object is illuminated by the spectral powerdistribution and a case (dotted line) where an object is illuminated bycalculational reference light corresponding to the spectral powerdistribution (drive point C);

FIG. 98 is a diagram showing a spectral power distribution when theradiant flux ratio of the light emitting area 1, the light emitting area2 and the light emitting area 3 is 1:1:1 in Example 8, and a CIELABcolor space on which are respectively plotted a* values and b* values ofthe 15 Munsell renotation color samples when respectively assuming acase (solid line) where an object is illuminated by the spectral powerdistribution and a case (dotted line) where an object is illuminated bycalculational reference light corresponding to the spectral powerdistribution (drive point D);

FIG. 99 is the CIE 1976 u′v′ chromaticity diagram on which thechromaticity of the drive points A to E in Example 8 are indicated. Thetwo-dot chain line in FIG. 99 is a range of D_(uv) that satisfiesCondition 1 of the first embodiment of the first to fourth inventions ofthe present invention;

FIG. 100 is a diagram showing the deposition of the light emitting areasof the packaged LED used for Example 8;

FIG. 101 is a graph showing the transmission characteristic of thecontrol element (filter) used for Example 9;

FIG. 102 is a graph showing the spectral power distributions in theReference Example 1 and Example 9. In FIG. 102, the dotted lineindicates the relative spectral power distribution in the ReferenceExample 1 that does not include a control element, and the solid lineindicates the relative spectral power distribution radiating onto theaxis in Example 9 that includes a control element;

FIG. 103 are graphs showing the spectral power distributions ofReference Example 1 and Example 9, and the CIELAB plots plotting boththe a* value and the b* value of the 15 color samples assuming the caseof illuminating with these spectral power distributions, and with acalculational reference light (black-body radiator) having a CCTcorresponding to these spectral power distributions respectively (thedotted line in the CIELAB plot indicates the result of the referencelight, and the solid line indicates the result of the packaged LED);

FIG. 104 is a graph showing transmission characteristics of the controlelement (filter) used for Example 10;

FIG. 105 is a graph showing the spectral power distributions in theReference Comparative Example 1 and Example 10. In FIG. 105, the dottedline indicates the relative spectral power distribution in the ReferenceComparative Example 1 that does not include a control element, and thesolid line indicates the relative spectral power distribution radiatingonto the axis in Example 10 that includes a control element;

FIG. 106 are graphs showing the spectral power distributions ofReference Comparative Example 1 and Example 10, and the CIELAB plotsplotting both the a* value and the b* value of the 15 color samplesassuming the case of illuminating with these spectral powerdistributions, and with a calculational reference light (black-bodyradiator) having a CCT corresponding to these spectral powerdistributions respectively (the dotted line in the CIELAB plot indicatesthe result of the reference light, and the solid line indicates theresult of the packaged LED);

FIG. 107 is a graph showing the spectral power distributions in theReference Comparative Example 2 and Comparative Example 2. In FIG. 107,the dotted line indicates the relative spectral power distribution inthe Reference Comparative Example 2 that does not include a controlelement, and the solid line indicates the relative spectral powerdistribution radiating onto the axis in Comparative Example 2 thatincludes a control element;

FIG. 108 are graphs showing the spectral power distributions ofReference Comparative Example 2 and Comparative Example 2, and theCIELAB plots plotting both the a* value and the b* value of the 15 colorsamples assuming the case of illuminating with these spectral powerdistributions, and with a calculational reference light (black-bodyradiator) having a CCT corresponding to these spectral powerdistributions respectively (the dotted line in the CIELAB plot indicatesthe result of the reference light, and the solid line indicates theresult of the packaged LED);

FIG. 109 is a graph showing the spectral power distributions in theReference Example 2 and Example 11. In FIG. 109, the dotted lineindicates the relative spectral power distribution in the ReferenceExample 2 that does not include a control element, and the solid lineindicates the relative spectral power distribution radiating onto theaxis in Example 11 that includes a control element;

FIG. 110 are graphs showing the spectral power distributions ofReference Example 2 and Example 11, and the CIELAB plots plotting boththe a* value and the b* value of the 15 color samples assuming the caseof illuminating with these spectral power distributions, and with acalculational reference light (black-body radiator) having a CCTcorresponding to these spectral power distributions respectively (thedotted line in the CIELAB plot indicates the result of the referencelight, and the solid line indicates the result of the packaged LED);

FIG. 111 is a graph showing the spectral power distributions in theReference Comparative Example 3 and Example 12. In FIG. 111, the dottedline indicates the relative spectral power distribution in the ReferenceComparative Example 3 that does not include a control element, and thesolid line indicates the relative spectral power distribution radiatingonto the axis in Example 12 that includes a control element;

FIG. 112 are graphs showing the spectral power distributions ofReference Comparative Example 3 and Example 12, and the CIELAB plotsplotting both the a* value and the b* value of the 15 color samplesassuming the case of illuminating with these spectral powerdistributions, and with a calculational reference light (black-bodyradiator) having a CCT corresponding to these spectral powerdistributions respectively (the dotted line in the CIELAB plot indicatesthe result of the reference light, and the solid line indicates theresult of the packaged LED);

FIG. 113 is a diagram showing an example of the light emitting areas ofthe light-emitting device according to the first embodiment of the firstinvention of the present invention;

FIG. 114 is a schematic diagram showing an example of the light-emittingdevice according to the second embodiment of the first invention of thepresent invention;

FIG. 115 is a schematic diagram showing an example of the light-emittingdevice according to the second embodiment of the first invention of thepresent invention.

DESCRIPTION OF EMBODIMENTS

While the present invention will be described in detail hereinafter, itis to be understood that the present invention is not limited to theembodiments described below and that various modifications can be madewithout departing from the spirit and scope of the invention.

Moreover, in a light-emitting device according to the first to thirdinventions of the present invention specifies the invention based onlight in a “main radiant direction” among light emitted from alight-emitting device. Therefore, light-emitting devices capable ofradiating light including light in a “main radiant direction” whichmeets requirements of the first embodiments of the first to fourthinventions of the present invention are to be included in the spirit andscope of the first embodiments of the first to fourth inventions of thepresent invention.

In addition, an illumination method according to a first embodiment ofthe fourth invention of the present invention specifies the inventionbased on light at a position where an object is illuminated in a casewhere light emitted from a light-emitting device used in theillumination method illuminates the object. Therefore, illuminationmethods used by light-emitting devices capable of emitting light at a“position where an object is illuminated” which meets requirements ofthe first embodiment of the first to fourth inventions of the presentinvention are to be included in the spirit and scope of the firstembodiment of the first to fourth inventions of the present invention.

According to the second embodiment of the first invention of the presentinvention, on the other hand, the spectral power distribution Φ_(elm)(λ)of the light, emitted from a light-emitting element included in thelight-emitting device in a main radiant direction, is controlled by acontrol element included in the light-emitting device, and the light isthen emitted in the “main radiant direction”. Therefore, light-emittingdevices capable of radiating light including light in a “main radiantdirection” which meets requirements of the second embodiments of thefirst, second, fourth and fifth inventions of the present inventioncontrolled by the control element are to be included in the spirit andscope of the second embodiments of the first, second, fourth and fifthinventions of the present invention. According to the second embodimentof the fifth and the second inventions of the present invention, amethod for manufacturing and a method for designing a light-emittingdevice that can irradiate light, including light in the “main radiantdirection” which satisfies the requirement of the second embodiment ofthe first, second, fourth and fifth inventions of the present inventioncontrolled by the control element, are provided, and manufacturing anddesigning of the light-emitting device by disposing the control elementthat belongs to the scope of the second embodiment of the first, second,fourth and fifth inventions of the present invention. In addition, anillumination method according to a second embodiment of the fourthinvention of the present invention specifies the invention based onlight at a position where an object is illuminated in a case where lightemitted from the light-emitting device illuminates the object.Therefore, illumination methods used by light-emitting devices capableof emitting light at a “position where an object is illuminated” whichmeets requirements of the second embodiment of the first, second, fourthand fifth inventions of the present invention by disposing the controlelement are to be included in the spirit and scope of the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention.

As used herein, the “main radiant direction” according to the first tothird inventions of the present invention refers to a direction in whichlight is radiated over a suitable range and in a suitable orientationwhich are in line with usage of the light-emitting device.

For example, the “main radiant direction” may be a direction in whichluminous intensity or luminance of the light-emitting device is maximumor locally maximum.

In addition, the “main radiant direction” may be a direction having afinite range including a direction in which the luminous intensity orthe luminance of the light-emitting device is maximum or locallymaximum.

In addition, the main radiant direction may be a direction in whichradiant intensity or radiance of the light-emitting device is maximum orlocally maximum.

In addition, the “main radiant direction” may be a direction having afinite range including a direction in which the radiant intensity or theradiance of the light-emitting device is maximum or locally maximum.

Specific examples will be given below.

When the light-emitting device is an individual light-emitting diode(LED), an individual packaged LED, an individual LED module, anindividual LED bulb, an individual composite lamp constituted by afluorescent lamp and a semiconductor light-emitting element, anindividual composite lamp constituted by an incandescent bulb and asemiconductor light-emitting element, or the like, a main radiantdirection may be a vertical direction of each light-emitting device orwithin a finite solid angle which includes the vertical direction andwhich ranges between, for example, a maximum of π (sr) and a minimum ofπ/100 (sr).

When the light-emitting device is an LED lighting fixture in which alens, a reflection mechanism, and the like is added to the packaged LEDor the like or a lighting fixture which incorporates a fluorescent lampand a semiconductor light-emitting element and which has lightdistribution characteristics applicable to so-called direct lightinguse, semi-direct lighting use, general diffused lighting use,direct/indirect lighting use, semi-indirect lighting use, and indirectlighting use, a main radiant direction may be a vertical direction ofeach light-emitting device or within a finite solid angle which includesthe vertical direction and which ranges between, for example, a maximumof π (sr) and a minimum of π/100 (sr). In addition, the main radiantdirection may be a direction in which luminous intensity or luminance ofthe light-emitting device is maximum or locally maximum. Furthermore,the main radiant direction may be within a finite solid angle thatincludes a direction in which luminous intensity or luminance of thelight-emitting device is maximum or locally maximum and which rangesbetween, for example, a maximum of π (sr) and a minimum of π/100 (sr).In addition, the main radiant direction may be a direction in whichradiant intensity or radiance of the light-emitting device is maximum orlocally maximum. Furthermore, the main radiant direction may be within afinite solid angle which includes a direction in which radiant intensityor radiance of the light-emitting device is maximum or locally maximumand which ranges between, for example, a maximum of π (sr) and a minimumof π/100 (sr).

When the light-emitting device is a lighting system in which a pluralityof the LED lighting fixtures or lighting fixtures incorporating afluorescent lamp is mounted, the main radiant direction may be avertical direction of a planar center of each light-emitting device orwithin a finite solid angle which includes the vertical direction andwhich ranges between, for example, a maximum of π (sr) and a minimum ofπ/100 (sr). In addition, the main radiant direction may be a directionin which luminous intensity or luminance of the light-emitting device ismaximum or locally maximum. Furthermore, the main radiant direction maybe within a finite solid angle which includes a direction in whichluminous intensity or luminance of the light-emitting device is maximumor locally maximum and which ranges between, for example, a maximum of π(sr) and a minimum of π/100 (sr). In addition, the main radiantdirection may be a direction in which radiant intensity or radiance ofthe light-emitting device is maximum or locally maximum. Furthermore,the main radiant direction may be within a finite solid angle whichincludes a direction in which radiant intensity or radiance of thelight-emitting device is maximum or locally maximum and which rangesbetween, for example, a maximum of π (sr) and a minimum of π/100 (sr).

A spectral power distribution of light emitted in the main radiantdirection by the light-emitting device is favorably measured at adistance where illuminance at a measuring point is a practicalilluminance (as will be described later, 150 lx or higher and 5000 lx orlower).

In the present specification, reference light as defined by CIE which isused in calculations for estimating a mathematical color appearance maysometimes be referred to as reference light, calculational referencelight, and the like. On the other hand, experimental reference lightwhich is used when making actual visual comparisons or, in other words,light from an incandescent bulb which incorporates a tungsten filamentor the like may sometimes be referred to as reference light,experimental reference light and the like. In addition, light with ahigh R_(a) and a high R_(i) which is estimated to have a colorappearance that is close to reference light such as light from an LEDlight source which is used as alternate light for experimental referencelight in a visual comparison experiment may sometimes be referred to asreference light, experimental pseudo-reference light and the like.Furthermore, light that is an object of a mathematical or experimentalexamination may sometimes be referred to as test light in contrast toreference light.

The light-emitting device according to the first embodiment of the firstinvention of the present invention includes M number of light emittingareas (M is 2 or greater natural number). In this description, lightemitting areas that emit light in an equivalent spectral powerdistribution (allowing a general dispersion generated in themanufacturing steps) are called the “same type of light emitting areas”.In other words, even if the light emitting areas are physicallyseparated and disposed with a distance, these light emitting areas areof a same type if they emit lights in an equivalent spectral powerdistribution (allowing a general dispersion generated in themanufacturing steps). This means that the light-emitting device,according to the first embodiment of the first invention of the presentinvention, includes two or more types of light emitting areas from whichlights in mutually different spectral power distributions are emitted.

At least one light emitting area of the plurality of types of lightemitting areas includes a semiconductor light-emitting element as thelight-emitting element. Only if at least one light emitting areaincludes a semiconductor light-emitting element as the light-emittingelement, the light-emitting element included in each light emitting areais not limited. The light-emitting elements, other than thesemiconductor light-emitting element, can be any light-emitting elementif various supplied energies can be converted into electromagneticradiation energy, and the electromagnetic radiation energy includesvisible light in a range from 380 nm to 780 nm. For example, a hotfilament, a fluorescent tube, a high pressure sodium lamp, a laser, anda secondary harmonic generation (SHG) source that can convert electricenergy can be used. A phosphor or the like that can convert light energycan also be used.

The configuration of the light-emitting device according to the firstembodiment of the first invention of the present invention is notespecially limited, only if a plurality of light emitting areas,including a light emitting area which has a semiconductor light-emittingelement as the light-emitting element, exists therein. An individualsemiconductor light-emitting element to which a lead or the like as aconducting mechanism is added or a packaged LED to which a heatdissipating mechanism is further added and integrated with a phosphor orthe like may be adopted as the light emitting area.

In addition, the light-emitting device can be an LED module in which arobust heat dissipating mechanism is added to one or more packaged LEDsand which is generally mounted with a plurality of packaged LEDs may beadopted as the light-emitting device. Furthermore, an LED lightingfixture in which a lens, a reflecting mechanism, and the like are addedto a packaged LED may be adopted. Moreover, a lighting system whichsupports a large number of LED lighting fixtures or the like and whichis configured to be capable of illuminating an object may be adopted.The light-emitting device according to the present embodimentencompasses all of the above.

In the light-emitting device according to the first embodiment of thefirst invention of the present invention, when φ_(SSL)N(λ) (N is in the1 to M range) is the spectral power distribution of the light emittedfrom each light emitting area, φ_(SSL)(λ), which is the spectral powerdistribution of all the lights emitted from the light-emitting device inthe radiant direction, is given by

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 38} \rbrack \\{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{{N(\lambda)}.}}}}\end{matrix}$This will be described with reference to FIG. 113.

The light-emitting device 100 in FIG. 113 is one mode of thelight-emitting device according to the first embodiment of the firstinvention of the present invention. The light-emitting device 100 is thecase when M in the above expression is M=5, and 5 (five types of) lightemitting areas, that is, the light emitting area 1 to the light emittingarea 5, are included. Each light emitting area has a semiconductorlight-emitting element 6 as the light-emitting element.

When φ_(SSL)1(λ) is the spectral power distribution of the light emittedfrom the light emitting area 1, λ_(SSL)2(λ) is the spectral powerdistribution of the light emitted from the light emitting area 2,φ_(SSL)3(λ) is the spectral power distribution of the light emitted fromthe light emitting area 3, φ_(SSL)4(λ) is the spectral powerdistribution of the light emitted from the light emitting area 4, andφ_(SSL)5(λ) is the spectral power distribution of the light emitted fromthe light emitting area 5, then the spectral power distributionφ_(SSL)(λ) of all the lights emitted from the light-emitting device inthe radiant direction is given by

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 39} \rbrack & \; \\\begin{matrix}{{\phi_{SSL}(\lambda)} = {{\phi_{SSL}1(\lambda)} + {\phi_{SSL}2(\lambda)} + {\phi_{SSL}3(\lambda)} + {\phi_{SSL}4(\lambda)} + {\phi_{SSL}5(\lambda)}}} \\{= {\sum\limits_{N = 1}^{5}\;{\phi_{SSL}{{N(\lambda)}.}}}}\end{matrix} & \;\end{matrix}$In other words, when N is 1 to M, φ_(SSL)(λ) can be given by

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 40} \rbrack \\{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{{N(\lambda)}.}}}}\end{matrix}$

According to the first embodiment of the first to fourth inventions ofthe present invention, the appearance of colors can be variable whileimplementing a natural, vivid, highly visible and comfortable appearanceof colors and appearance of objects as if the objects are seen outdoors.In concrete terms, the light-emitting device, including light emittingareas that can satisfy predetermined conditions by changing the luminousflux amount and/or radiant flux amount emitted from each light emittingarea, is provided.

The light-emitting device according to the second embodiment of thefirst invention of the present invention has: a light-emitting elementthat includes a semiconductor light-emitting element; and a controlelement.

The light-emitting element according to the second embodiment of thefirst, second, fourth and fifth inventions of the present inventionincludes the semiconductor light-emitting element as an essentialelement, but may also include other light-emitting elements. Otherlight-emitting elements are not especially limited if various suppliedenergies can be converted into electromagnetic radiation energy, and theelectromagnetic radiation energy includes visible light in a range from380 nm to 780 nm. For example, a hot filament, a fluorescent tube, ahigh pressure sodium lamp, a laser, and a secondary harmonic generation(SHG) source that can convert electric energy can be used. A phosphorthat can convert light energy can also be used.

The control element according to the second embodiment of the first,second, fourth and fifth inventions of the present invention is apassive element that itself has no amplifying function, and is notespecially limited if the intensity modulation for each wavelength canbe performed in an appropriate range, on light that is emitted from alight-emitting element or a light-emitting device having relatively lowlevel processing, in the main direction, and can constitute alight-emitting device having high level processing. Examples of thecontrol element of the second embodiment of the first, second, fourthand fifth inventions of the present invention are passive devices, suchas a reflection mirror, an optical filter and an optical lens. Thecontrol element according to the second embodiment of the first, second,fourth and fifth inventions of the present invention may be anabsorption material that is disposed in the sealing material of thepackaged LED, so as to perform intensity modulation for each wavelengthin an appropriate range. However, a light-emitting element and areflection mirror, optical filter, an absorption material or the likethat can perform intensity modulation, of which wavelength dependency islow, on the light emitted from a light-emitting device having relativelylow level processing, are not included in the control element.

An overview of the light-emitting device according to the secondembodiment of the first invention of the present invention will befurther described with reference to FIG. 114. In the example of FIG.114, an LED chip 52, which is a semiconductor light-emitting element,and a phosphor 54 are included as a light-emitting element, and apackaged LED 510, which is a light-emitting device having low levelprocessing, is constituted by this light-emitting element and by otherconstituents, such as sealing material 56 and packaging material 53. Inthis case, an optical filter 55 that performs intensity modulation foreach wavelength in an appropriate range is disposed in the reliantdirection of the light of the packaged LED 510 as the control element,and thereby an LED light bulb 520, which is a light-emitting devicehaving high level processing, is configured as a result. This LED lightbulb 520 can be the light-emitting device according to the secondembodiment of the first invention of the present invention.

An overview of the light-emitting device according to the secondembodiment of the first invention of the present invention will befurther described with reference to FIG. 115. It is assumed that a blueLED chip 52 a, a green LED chip 52 b and a red LED chip 52 c, which aresemiconductor light-emitting elements, are included as thelight-emitting elements, and the packaged LED 510, which is alight-emitting device having low level processing, is constituted bythese light-emitting elements and other constituents, such as sealingmaterial 56 and packaging material 53. In this case, an optical filter55 which functions as a control element is disposed in the radiantdirection of the packaged LED 510, and thereby an LED light bulb 520,which is a light-emitting device having high level processing, isconfigured as a result. This LED light bulb 520 can be thelight-emitting device according to the second embodiment of the firstinvention of the present invention. Further, n number of LED light bulbs520 are disposed and m number of incandescent bulbs 511, which arelight-emitting devices having mid-level processing, including a heatfilament 52 d as the light-emitting element, are disposed, whereby anillumination system 530, which is a light-emitting device having highlevel processing, is constructed. The illumination system can be thelight-emitting device according to the second embodiment of the firstinvention of the present invention.

The light (radiant flux) emitted from the light-emitting element in themain radiant direction that is referred to in this description is atotal of the light (radiant flux) emitted from all the light-emittingelements in the main radiant direction, and here this spectral powerdistribution is denoted as Φ_(elm). Φ_(elm)(λ) is a function of thewavelength λ. Φ_(elm)(λ) can be measured by performing radiantmeasurement for the light-emitting device, from which the controlelement according to this description is removed. In the case of thelight-emitting device which includes the LED chip and the phosphor asthe light-emitting elements, and which has an optical filter thatperforms intensity modulation for each wavelength in an appropriaterange as the control element, as shown in FIG. 114, Φ_(elm)(λ) isacquired if the spectral power distribution of the light irradiated inthe main radiant direction from the light-emitting device from which theoptical filter is removed is measured. In other words, Φ_(elm)(λ) can beacquired if the spectral power distribution of the light emitted in themain radiant direction of the packaged LED, which is the light-emittingdevice having a low level processing is measured.

If there is “a light-emitting device having mid-level processing or alight-emitting device having high level processing” which partiallyexists in “a light-emitting device having even higher level processing”as shown in FIG. 115, then the spectral power distribution of light,which is irradiated in the main radiant direction from thelight-emitting device including n number of packaged LEDs and m numberof incandescent bulbs in a state where the control element is disabled,can be regarded as Φ_(elm)(λ).

The light-emitting device according to the second embodiment of thefirst invention of the present invention includes a light-emittingelement including a semiconductor light-emitting element. For thelight-emitting element, the semiconductor light-emitting element isincluded as an essential element, but another light-emitting element maybe included. The other light-emitting elements are not particularlylimited as long as it can emit light corresponding to a range of 380 nmto 780 nm in some way, and examples of the light-emitting elementinclude thermal emission light from a hot filament or the like, electricdischarge emission light from a fluorescent tube, a high-pressure sodiumlamp, or the like, stimulated emission light from a laser or the like,spontaneous emission light from a semiconductor light-emitting element,and spontaneous emission light from a phosphor. The light-emittingdevice according to the present embodiment includes a control element aswell, but other configurations are not especially limited. An individualsemiconductor light-emitting element to which a lead or the like as aconducting mechanism is added or a packaged LED to which a heatdissipating mechanism is further added and integrated with a phosphor orthe like may be adopted as the light-emitting element. Thelight-emitting device can be an LED module in which a robust heatdissipating mechanism is added to one or more packaged LEDs and which isgenerally mounted with a plurality of packaged LEDs may be adopted asthe light-emitting device. Furthermore, an LED lighting fixture in whicha lens, a reflecting mechanism, and the like are added to a packaged LEDmay be adopted. Moreover, a lighting system which supports a largenumber of LED lighting fixtures or the like and which is configured tobe capable of illuminating an object may be adopted. Still further, forexample, an individual electric discharge tube to which a mechanismcapable of applying a high voltage is added or an electric dischargetube having a phosphor arranged in the interior or circumference thereofmay be adopted as the light-emitting device according to the presentembodiment when the light-emitting device includes an electric dischargetube as the light-emitting element. A lighting fixture in which aplurality of fluorescent tubes incorporating one or more phosphors aredisposed may also be adopted. Furthermore, a lighting fixture to which areflecting mechanism or the like is added may be adopted. Moreover, acontrol circuit or the like may be added to the lighting fixture toprovide a lighting system. The light-emitting device according to thepresent embodiment encompasses all of the above.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, the light-emitting element may be alight-emitting device. In other words, the light-emitting elementaccording to the second embodiment of the first, second, fourth andfifth inventions of the present invention may be an LED module, an LEDlighting fixture, a lighting system, or a lighting fixture havinganother mechanism.

The present inventor has discovered a radiometric property or aphotometric property common to spectra or spectral power distributionscapable of realizing a color appearance or an object appearance which isas natural, vivid, highly visible, and comfortable as though perceivedoutdoors in a high-illuminance environment even in an ordinary indoorilluminance environment. The present inventor further ascertained, froma colorimetric perspective, in what way the color appearance of thecolor samples having specific spectral reflectance characteristics whenassuming that the color is illuminated by light having theaforementioned spectrum or spectral power distribution changes (or doesnot change) when the object described above is achieved in comparisonwith a case where illumination by calculational reference light isassumed, and collectively reached the present invention. In addition,the present inventor discovered that the appearance of colors can bevariable if a plurality of light emitting areas is included. Further,the present inventor examined the spectral power distribution of alight-emitting device that can implement both a natural, vivid, highlyvisible and comfortable appearance of colors and appearance of objects,and suppress the secondary influence of light irradiation onto theillumination object, which is of concern in the case when theillumination object is, for example, an art object or perishable food,and reached the present invention as a result.

It should be noted that the present invention was made based onexperimental facts which defy common and conventional wisdom.

Specific circumstances leading to the invention can be summarized asfollows.

Summary of Circumstances Leading to Invention First Embodiment of Firstto Fourth Inventions of the Present Invention

As a first step, a baseline mathematical examination was conducted onthe assumption of: A) a packaged LED light source incorporating both asemiconductor light-emitting element and a phosphor; and B) a packagedLED light source which does not include a phosphor and which onlyincorporates a semiconductor light-emitting element as a light-emittingelement, which both have a high degree of freedom in setting a spectralpower distribution.

In doing so, by employing, as a guideline, a mathematical variationregarding the color appearance of a color sample having specificspectral reflectance characteristics between a case where illuminationby calculational reference light is assumed and a case whereillumination by test light that is an examination object is assumed,test lights causing changes in hue, saturation (chroma) or the like wereexamined in detail. In particular, while being aware of the Hunt effectin an ordinary indoor environment where illuminance drops to around 1/10to 1/1000 as compared to outdoors, the mathematical examination focusedon light with variations in saturation of color appearance of anilluminated object.

As a second step, prototypes of a packaged LED light source and alighting fixture incorporating the packaged LED light source were madebased on the mathematically examined test light. In addition, forcomparative visual experiments to be performed in a third step, anincandescent bulb with a tungsten filament was prepared as experimentalreference light. Furthermore, prototypes of a light source capable ofemitting light (experimental pseudo-reference light) with high R_(a) andhigh R_(i) and which produces a color appearance that is close to thatof calculational reference light as well as a lighting fixtureincorporating the light source were also made. Moreover, for visualexperiments using the above, in order to have subjects evaluate a colorappearance when an object is illuminated by experimental reference lightor experimental pseudo-reference light and a color appearance when theobject is illuminated by light (test light) of a lighting fixtureincorporating the packaged LED light source, an illumination experimentsystem capable of illuminating different illuminating light on a largenumber of observation objects was fabricated.

As a third step, comparative visual experiments were performed. Dueconsideration was given to preparing chromatic objects so that colors ofthe observation objects covered all hues including purple, bluishpurple, blue, greenish blue, green, yellowish green, yellow, reddishyellow, red, and reddish purple. Achromatic objects such as whiteobjects and black objects were also prepared. These chromatic andachromatic objects were prepared in wide varieties and in large numbersincluding still objects, fresh flowers, food, clothing, and printedmaterial. At this point, the subjects were asked to evaluate a colorappearance when the objects were illuminated by experimental referencelight or experimental pseudo-reference light and a color appearance whenthe objects were illuminated by test light. Comparisons between theformer and the latter were performed at similar CCTs and similarilluminance. The subjects were asked to perform evaluations from theperspective of which of the lights had relatively achieved a colorappearance or an object appearance that is as natural, vivid, highlyvisible, and comfortable as though perceived outdoors. The subjects werealso asked the reasons for their judgment regarding which is superior orinferior.

As a fourth step, radiometric properties and photometric properties ofthe experimental reference light/experimental pseudo-reference light andthe test light were extracted from actual measured values. Furthermore,a difference in colorimetric properties regarding a color appearance ofcolor samples having specific spectral reflectance characteristics whichdiffers from the observation objects described above between a casewhere illumination at a spectral power distribution of calculationalreference light is calculationally assumed and a case where illuminationat a spectral power distribution of an actually measured experimentalreference light/experimental pseudo-reference light/test light iscalculationally assumed was compared with the evaluations by thesubjects in the visual experiments, and characteristics of theillumination method or the light-emitting device determined to be trulycomfortable were extracted.

As a fifth step, the present inventor examined how the appearance ofcolors change by adjusting the luminous flux amount and/or the radiantflux amount of each light emitting area in the light-emitting devicethat includes a plurality of light emitting areas.

Moreover, contents of the fifth step also represent examples/comparativeexamples of the first embodiment of the first to fourth inventions ofthe present invention, contents of the third and fourth steps alsorepresent examples/comparative examples of the illumination methodaccording to the first embodiment of the fourth invention of the presentinvention, and contents of the second, third and fourth steps alsorepresent examples/comparative examples of the first embodiment of thefirst to third inventions of the present invention.

Second Embodiment of First, Second, Fourth and Fifth Inventions of thePresent Invention

As a first step, without taking functions of a control element intoconsideration, a baseline mathematical examination was conducted on theassumption of: A) a packaged LED light source incorporating both asemiconductor light-emitting element and a phosphor; and B) a packagedLED light source which does not include a phosphor and which onlyincorporates a semiconductor light-emitting element as a light-emittingelement, which both have a high degree of freedom in setting a spectralpower distribution.

In doing so, by employing, as a guideline, a mathematical variationregarding the color appearance of a color sample having specificspectral reflectance characteristics between a case where illuminationby calculational reference light is assumed and a case whereillumination by test light that is an examination object is assumed,test lights causing changes in hue, saturation (chroma), or the likewere examined in detail. In particular, while being aware of the Hunteffect in an ordinary indoor environment where illuminance drops toaround 1/10 to 1/1000 as compared to outdoors, the mathematicalexamination focused on light with variations in saturation of colorappearance of an illuminated object.

As a second step, prototypes of a packaged LED light source and alighting fixture incorporating the packaged LED light source were madebased on the mathematically examined test light. The functions of thecontrol element are not included in the lighting ficture. In addition,for comparative visual experiments to be performed in a third step, anincandescent bulb with a tungsten filament was prepared as experimentalreference light. Furthermore, prototypes of a light source capable ofemitting light (experimental pseudo-reference light) with high R_(a) andhigh R_(i) and which produces a color appearance that is close to thatof calculational reference light as well as a lighting fixtureincorporating the light source were also made. Moreover, for visualexperiments using the above, in order to have subjects evaluate a colorappearance when an object is illuminated by experimental reference lightor experimental pseudo-reference light and a color appearance when theobject is illuminated by light (test light) of a lighting fixtureincorporating the packaged LED light source, an illumination experimentsystem capable of illuminating different illuminating light on a largenumber of observation objects was fabricated.

As a third step, comparative visual experiments were performed by usinga lighting fixture and a lighting system that does not include thefunctions of the control element. Due consideration was given topreparing chromatic objects so that colors of the observation objectscovered all hues including purple, bluish purple, blue, greenish blue,green, yellowish green, yellow, reddish yellow, red, and reddish purple.Achromatic objects such as white objects and black objects were alsoprepared. These chromatic and achromatic objects were prepared in widevarieties and in large numbers including still objects, fresh flowers,food, clothing, and printed material. At this point, the subjects wereasked to evaluate a color appearance when the objects were illuminatedby experimental reference light or experimental pseudo-reference lightand a color appearance when the objects were illuminated by test light.Comparisons between the former and the latter were performed at similarCCTs and similar illuminance. The subjects were asked to performevaluations from the perspective of which of the lights had relativelyachieved a color appearance or an object appearance that is as natural,vivid, highly visible, and comfortable as though perceived outdoors. Thesubjects were also asked the reasons for their judgment regarding whichis superior or inferior.

As a fourth step, radiometric properties and photometric properties ofthe experimental reference light/experimental pseudo-reference light andthe test light were extracted from actual measured values. Furthermore,a difference in colorimetric properties regarding a color appearance ofcolor samples having specific spectral reflectance characteristics whichdiffers from the observation objects described above between a casewhere illumination at a spectral power distribution of calculationalreference light is calculationally assumed and a case where illuminationat a spectral power distribution of an actually measured experimentalreference light/experimental pseudo-reference light/test light iscalculationally assumed was compared with the evaluations by thesubjects in the visual experiments, and characteristics of theillumination method or the light-emitting device determined to be trulycomfortable were extracted.

As the fifth step, the present inventor carried out an examination tointroduce a control element to a light-emitting device that does notinclude a control element.

Moreover, contents of the third and fourth steps also representreference examples/reference comparative examples of the secondembodiment of the first and fifth inventions of the present invention,and contents of the fifth step also represents examples/comparativeexamples of the second embodiment of the first, second, fourth and fifthinventions of the present invention.

[Quantification Method of Color Samples' Selection and Color Appearance]

In the first step, in consideration of the Hunt effect, a spectral powerdistribution at a position where light emitted from a light-emittingdevice mainly examined in the illumination method according to thefourth invention of the present invention illuminates an object or aspectral power distribution of light in a main radiant direction whichis emitted by the light-emitting device according to the first inventionof the present invention was assumed to vary saturation of anilluminated object from a case where illumination is performed usingreference light. At this point, the following selections were made inorder to quantify a color appearance or a variation thereof.

It was considered that, in order to quantitatively evaluate a colorappearance from a spectral power distribution, a color sample withobvious mathematical spectral reflectance characteristics is favorablydefined and a difference in color appearance of the color sample betweena case of illumination by calculational reference light and a case ofillumination by test light is adopted as an index.

Although test colors used in CRI are general choices, color samples R₁to R₈ which are used when deriving an average color rendering index orthe like are color samples with intermediate chroma and were thereforeconsidered unsuitable when discussing saturation of high-chroma colors.In addition, while R₉ to R₁₂ are high-chroma color samples, there arenot enough samples for a detailed discussion covering a range of all hueangles.

Therefore, it was decided that 15 color samples (one color sample perhue) be selected from color samples which have the highest chroma andwhich are positioned outermost in a Munsell color circle according tothe Munsell renotation color system. Moreover, these are the same colorsamples used in CQS (Color Quality Scale) (versions 7.4 and 7.5) that isa new color rendition metric proposed by NIST (National Institute ofStandards and Technology), U.S.A. The 15 color samples used in the firstto fifth inventions of the present invention will be listed below. Inaddition, a number assigned for convenience sake are provided beforeeach color sample. Moreover, in the present specification, these numberswill sometimes be represented by n. For example, n=3 signifies “5PB4/12”. n denotes a natural number from 1 to 15.

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

In the first to fifth inventions of the present invention, from theperspective of deriving various indices, an attempt was made to quantifyin what way the color appearance of the 15 color samples listed abovechanges (or does not change) between a case where the colors are assumedto be illuminated by calculational reference light and a case where thecolors are assumed to be illuminated by test light when a colorappearance or an object appearance that is as natural, vivid, highlyvisible, and comfortable as though perceived in an outdoorhigh-illuminance environment is achieved even in an ordinary indoorilluminance environment, and to extract results of the quantification asa color rendering property that should be attained by a light-emittingdevice.

Moreover, selection of a color space and selection of a chromaticadaptation formula are also important when quantitatively evaluatingcolor appearance that is mathematically derived from the spectral powerdistributions described above. In the first to fifth inventions of thepresent invention, CIE 1976 L*a*b* (CIELAB) that is a uniform colorspace currently recommended by the CIE was used. In addition, CMCCAT2000(Colour Measurement Committee's Chromatic Adaptation Transform of 2000)was adopted for chromatic adaptation calculation.

Chromaticity Points Derived from Spectral Power Distribution at Positionwhere Object is Illuminated or from Spectral Power Distribution of Lightin Main Radiant Direction Emitted from Light-Emitting Device FirstEmbodiment of First to Fourth Inventions of the Present Invention

In the first step, selection of a chromaticity point of a light sourceis also important when making various prototypes of a packaged LED lightsource. Although chromaticity derived from a light source, a spectralpower distribution at a position where an object is illuminated by lightfrom the light source, or a spectral power distribution of light in amain radiant direction emitted from a light-emitting device can bedefined by, for example, a CIE 1931 (x,y) chromaticity diagram, thederived chromaticity is favorably discussed using a CIE 1976 (u′,v′)chromaticity diagram which is a more uniform chromaticity diagram. Inaddition, when describing a position on a chromaticity diagram using aCCT and D_(uv), a (u′, (⅔)v′) chromaticity diagram (synonymous with aCIE 1960 (u,v) chromaticity diagram) is particularly used. Moreover,D_(uv) as described in the present specification is an amount defined byANSI C78.377 and represents a distance of closest approach to ablack-body radiation locus on a (u′,(⅔)v′) chromaticity diagram as anabsolute value thereof. Furthermore, a positive sign means that achromaticity point of a light-emitting device is above (on a side wherev′ is greater than) the black-body radiation locus, and a negative signmeans that the chromaticity point of the light-emitting device is below(on a side where v′ is smaller than) the black-body radiation locus.

Chromaticity Points Derived from Spectral Power Distribution of Light inMain Radiant Direction Emitted from Light-Emitting Device that does notInclude Control Element or from Spectral Power Distribution at Positionwhere Object is Illuminated Second Embodiment of First, Second, Fourthand Fifth Inventions of the Present Invention

In the first step, selection of a chromaticity point of a light sourceis also important when making various prototypes of a packaged LED lightsource. Although chromaticity derived from a light source, a spectralpower distribution at a position where an object is illuminated by lightfrom the light source, or a spectral power distribution of light in amain radiant direction emitted from a light-emitting device can bedefined by, for example, a CIE 1931 (x,y) chromaticity diagram, thederived chromaticity is favorably discussed using a CIE 1976 (u′, v′)chromaticity diagram which is a more uniform chromaticity diagram. Inaddition, when describing a position on a chromaticity diagram using aCCT and D_(uv), a (u′, (⅔)v′) chromaticity diagram (synonymous with aCIE 1960 (u,v) chromaticity diagram) is particularly used. Moreover,D_(uv) as described in the present specification is an amount defined byANSI C78.377 and represents a distance of closest approach to ablack-body radiation locus on a (u′, (⅔)v′) chromaticity diagram as anabsolute value thereof. Furthermore, a positive sign means that achromaticity point of a light-emitting device is above (on a side wherev′ is greater than) the black-body radiation locus, and a negative signmeans that the chromaticity point of the light-emitting device is below(on a side where v′ is smaller than) the black-body radiation locus.

[Examination of Calculation Regarding Saturation and D_(uv) Value]

The color appearance of an object can vary even if the chromaticitypoint remains the same. For example, the three spectral powerdistributions (test lights) shown in FIGS. 1, 2, and 3 represent anexample where the color appearance of an illuminated object is varied ata same chromaticity (CCT=5500 K, D_(u)=0.0000) when assuming a packagedLED which incorporates a semiconductor light-emitting element with apeak wavelength from 425 to 475 nm and which uses the semiconductorlight-emitting element as an excitation light source of a green phosphorand a red phosphor. While it is assumed that same materials are used forthe green phosphor and the red phosphor constituting the respectivespectral power distributions, in order to vary saturation, peakwavelengths of blue semiconductor light-emitting elements wererespectively set to 459 nm for FIG. 1, 475 nm for FIG. 2, and 425 nm forFIG. 3. Expected color appearances of the 15 color samples when assumingillumination at the respective spectral power distributions andillumination by calculational reference lights corresponding to therespective spectral power distributions are as depicted in the CIELABcolor spaces in FIGS. 1 to 3. In the drawings, points connected bydotted lines represent illumination by calculational reference light andpoints connected by solid lines represent illumination by test light.Moreover, while a direction perpendicular to the plane of paperrepresents lightness, only a* and b* axes were plotted for the sake ofconvenience.

The following findings were made regarding the spectral powerdistribution shown in FIG. 1. Based on calculations assumingillumination by calculational reference light and calculations assumingillumination by the test lights shown in the drawings, it was predictedthat the color appearances of the 15 color samples will closely resembleone another. In addition, Ra calculated based on the spectral powerdistribution was high at 95. In a case where illumination by the testlight shown in FIG. 2 is assumed, it was predicted that red and bluewill appear vivid but purple and green will dull as compared to a casewhere illumination by calculational reference light is assumed. Racalculated based on the spectral power distribution was relatively lowat 76. Conversely, in a case where illumination by the test light shownin FIG. 3 is assumed, it was predicted that purple and green will appearvivid but red and blue will dull as compared to a case whereillumination by calculational reference light is assumed. Ra calculatedbased on the spectral power distribution was relatively low at 76.

As described above, it was found that color appearances can be varied atthe same chromaticity point.

However, a detailed examination by the present inventor revealed that adegree of freedom of light in a vicinity of a black-body radiation locusor, in other words, light whose D_(uv) is in a vicinity of 0 isinsufficient to vary spectral power distribution and vary the colorappearance of the 15 high-saturation color samples. A more specificdescription will be given below.

For example, as shown in FIGS. 2 and 3, opposite tendencies werepredicted for a variation in saturation of red/blue and a variation insaturation of purple/green. In other words, it was predicted that whensaturation of a certain hue increases, saturation of another huedecreases. In addition, according to another examination, it wasdifficult to simultaneously vary saturation of a large number of huesusing a simple and feasible method. Therefore, when illuminating withlight in a vicinity of a black-body radiation locus or light whoseD_(uv) is in a vicinity of 0, it was difficult to simultaneously varysaturation of a large number of hues of the 15 high-chroma colorsamples, to relatively uniformly increase or decrease saturation of manyhues, and the like.

In consideration thereof, the present inventor mathematically examinedcolor appearances of the 15 color samples when assigning differentD_(uv) values to a plurality of spectral power distributions whilecomparing with a case where illumination is performed by calculationalreference light. Generally, it is thought that white appears greenishwhen D_(uv) is biased toward positive, white appears reddish when D_(uv)takes a negative value, and overall color appearance becomes unnaturalwhen D_(uv) deviates from the vicinity of 0. In particular, it isthought that coloring of white induces such perceptions. However, thepresent inventor conducted the following examination with an aim toincrease saturation controllability.

The eight spectral power distributions shown in FIGS. 4 to 11 representcalculation results of varying D_(uv) from −0.0500 to +0.0150 at a sameCCT (2700 K) when assuming a packaged LED which incorporates a bluesemiconductor light-emitting element with a peak wavelength of 459 nmand which uses the blue semiconductor light-emitting element as anexcitation light source of a green phosphor and a red phosphor. Expectedcolor appearances of the 15 color samples when assuming illumination atthe respective spectral power distributions (test lights) andillumination by calculational reference lights corresponding to therespective test lights are as represented in the CIELAB color spaces inFIGS. 4 to 11. In the drawings, points connected by dotted linesrepresent results regarding the calculational reference lights andpoints connected by solid lines represent results regarding respectivetest lights. Moreover, while a direction perpendicular to the plane ofpaper represents lightness, only a* and b* axes were plotted for thesake of convenience.

With the test light with D_(uv)=0.0000 shown in FIG. 4, it was predictedthat the color appearances of the 15 color samples will closely resembleone another between a case where illumination by calculational referencelight is assumed and a case where illumination by the test light shownin FIG. 4 is assumed. Ra calculated based on the spectral powerdistribution was high at 95.

The test lights shown in FIGS. 5 and 6 represent examples where D_(uv)is shifted in a positive direction from +0.0100 to +0.0150. As shown,when D_(uv) is shifted in the positive direction, it was predicted thatthe saturation of the 15 color samples can be varied over a wider huerange as compared to the case of the test light with D_(uv)=0.0000. Inaddition, it was found that the saturation of the 15 color samples canbe varied relatively uniformly as compared to the case of the test lightwith D_(uv)=0.0000. Moreover, with the case of the calculationalreference lights and the case of the test lights shown in FIGS. 5 and 6,it was predicted that the color appearances of almost all of the 15color samples with the exception of the blue to greenish blue regionwill dull when D_(uv) is shifted in the positive direction. Furthermore,a trend was also predicted in that the greater the shift of D_(uv) inthe positive direction, the lower the saturation. Ra calculated based onthe spectral power distributions of FIGS. 5 and 6 were 94 and 89,respectively.

On the other hand, the test lights shown in FIGS. 7 to 11 representexamples where D_(uv) is shifted in a negative direction from −0.0100 to−0.0500. As shown, when D_(uv) is shifted in the negative direction, itwas found that the saturation of the 15 color samples can be varied overa wider hue range as compared to the case of the test light withD_(uv)=0.0000. It was also found that the saturation of the 15 colorsamples can be varied relatively uniformly as compared to the case ofthe test light with D_(uv)=0.0000. Moreover, it was predicted that thecolor appearances of almost all of the 15 color samples with theexception of the blue to greenish blue region and the purple region willappear vividly when D_(uv) is shifted in the negative direction betweena case where illumination by the calculational reference lights isassumed and a case where illumination by the test lights shown in FIGS.7 to 11 is assumed. Furthermore, a trend was also predicted in that thegreater the shift of D_(uv) in the negative direction, the higher thesaturation. Ra calculated based on the spectral power distributions ofFIGS. 7 to 11 was 92, 88, 83, 77, and 71, respectively. According tocurrently prevailing belief, it was predicted that the greater the shiftof D_(uv) in the negative direction, the further the deviation of colorappearance from a case of illumination with reference light and,therefore, the greater the deterioration of color appearance.

In consideration thereof, the present inventor mathematically examinedpredictions of color appearances of the 15 most vivid color sampleswhich are positioned outermost in the Munsell renotation color systemwhen assigning various D_(uv) values to test lights in whichspectrum-forming light-emitting elements (light-emitting materials)differ from each other while comparing with calculational referencelights.

The 10 spectral power distributions shown in FIGS. 12 to 21 representresults of varying D_(uv) from −0.0500 to +0.0400 at a same CCT (4000 K)when a packaged LED incorporating four semiconductor light-emittingelements is assumed. Peak wavelengths of the four semiconductorlight-emitting elements were respectively set to 459 nm, 528 m, 591 nm,and 662 nm. Expected color appearances of the 15 color samples whenassuming illumination by the 10 respective test lights and illuminationby the calculational reference lights corresponding to the respectivetest lights are as represented in the CIELAB color spaces in FIGS. 12 to21. In the drawings, points connected by dotted lines represent resultsobtained with the calculational reference lights and points connected bysolid lines represent results regarding the respective test lights.Moreover, while a direction perpendicular to the plane of paperrepresents lightness, only a* and b* axes were plotted for the sake ofconvenience.

With the test light with D_(uv)=0.0000 shown in FIG. 12, it waspredicted that the color appearances of the 15 color samples willclosely resemble one another between a case where illumination by thecalculational reference light is assumed and a case where illuminationby the test light shown in FIG. 12 is assumed. Ra calculated based onthe spectral power distribution was high at 98.

The test lights shown in FIGS. 13 to 16 represent examples where D_(uv)is shifted in a positive direction from +0.0100 to +0.0400. As shown,when D_(uv) is shifted in the positive direction, it was found that thesaturation of the 15 color samples can be varied over a wider hue rangeas compared to the case of the test light with D_(uv)=0.0000. It wasalso found that the saturation of the 15 color samples can be variedrelatively uniformly as compared to the case of the test light withD_(uv)=0.0000. Moreover, it was predicted that the color appearances ofalmost all of the 15 color samples with the exception of the blue togreenish blue region and the red region will appear dull when D_(uv) isshifted in the positive direction between a case where illumination bythe calculational reference lights is assumed and a case whereillumination by the test lights shown in FIGS. 13 to 16 is assumed.Furthermore, a trend was also predicted in that the greater the shift ofD_(uv) in the positive direction, the lower the saturation. Racalculated based on the spectral power distributions of FIGS. 13 to 16was 95, 91, 86, and 77, respectively. According to currently prevailingbelief, it was predicted that the greater the shift of D_(uv) in thepositive direction, the further the deviation of color appearance from acase of illumination with reference light and, therefore, the greaterthe deterioration of color appearance.

On the other hand, the test lights shown in FIGS. 17 to 21 representexamples where D_(uv) is shifted in a negative direction from −0.0100 to−0.0500. As shown, when D_(uv) is shifted in the negative direction, itwas found that the saturation of the 15 color samples can be varied overa wider hue range as compared to the case of the test light withD_(uv)=0.0000. It was also found that the saturation of the 15 colorsamples can be varied relatively uniformly as compared to the case ofthe test light with D_(uv)=0.0000. Moreover, it was predicted that thecolor appearances of almost all of the 15 color samples with theexception of the blue to greenish blue region and the red region willappear vividly when D_(uv) is shifted in the negative direction betweena case where illumination by the calculational reference lights isassumed and a case where illumination by the test lights shown in FIGS.17 to 21 is assumed. Furthermore, a trend was also predicted in that thegreater the shift of D_(uv) in the negative direction, the higher thesaturation. Ra calculated based on the spectral power distributions ofFIGS. 17 to 21 was 95, 91, 86, 81, and 75, respectively. According tocurrently prevailing belief, it was predicted that the greater the shiftof D_(uv) in the negative direction, the further the deviation of colorappearance from a case of illumination with reference light and,therefore, the greater the deterioration of color appearance.

In addition, the present inventor mathematically examined predictions ofcolor appearances of the 15 most vivid color samples which arepositioned outermost in the Munsell renotation color system whenassigning various D_(uv) values to test lights in which spectrum-forminglight-emitting elements (light-emitting materials) further differ fromeach other while comparing with calculational reference light.

The 11 spectral power distributions shown in FIGS. 22 to 32 representcalculation results of varying D_(uv) from −0.0448 to +0.0496 at a closeCCT (approximately 5500 K) when assuming a packaged LED whichincorporates a purple semiconductor light-emitting element and whichuses the purple semiconductor light-emitting element as an excitationlight source of a blue phosphor, a green phosphor, and a red phosphor. Apeak wavelength of the incorporated semiconductor light-emitting elementwas set to 405 nm. Moreover, the result shown in FIG. 32 was obtainedwithout including a green phosphor in order to cause D_(uv) to take anexcessively negative value. Mathematically expected color appearances ofthe 15 color samples when assuming illumination by the 11 respectivetest lights and illumination by calculational reference lightscorresponding to the respective test lights are as represented in theCIELAB color spaces in FIGS. 22 to 32. In the drawings, points connectedby dotted lines represent results regarding the calculational referencelights and points connected by solid lines represent results regardingthe respective test lights. Moreover, while a direction perpendicular tothe plane of paper represents lightness, only a* and b* axes wereplotted for the sake of convenience.

With the test light with D_(uv)=0.0001 shown in FIG. 22, it waspredicted that the color appearances of the 15 color samples willclosely resemble one another between a case of the calculationalreference light and a case of the test light shown in FIG. 22. Racalculated based on the spectral power distribution was high at 96.

The test lights shown in FIGS. 23 to 27 represent examples where D_(uv)is shifted in a positive direction from +0.0100 to +0.0496. As shown,when D_(uv) is shifted in the positive direction, it was found that thesaturation of the 15 color samples can be varied over a wider hue rangeas compared to the case of the test light with D_(uv)=0.0001. It wasalso found that the saturation of the 15 color samples can be variedrelatively uniformly as compared to the case of the test light withD_(uv)=0.0001. Moreover, it was predicted that the color appearances ofalmost all of the 15 color samples with the exception of the blue regionwill appear dull when D_(uv) is shifted in the positive directionbetween a case where illumination by the calculational reference lightsis assumed and a case where illumination by the test lights shown inFIGS. 23 to 27 is assumed. Furthermore, a trend was also predicted inthat the greater the shift of D_(uv) in the positive direction, thelower the saturation. Ra calculated based on the spectral powerdistributions of FIGS. 23 to 27 was 92, 85, 76, 69, and 62,respectively. According to currently prevailing belief, it was predictedthat the greater the shift of D_(uv) in the positive direction, thefurther the deviation of color appearance from a case of illuminationwith reference light and, therefore, the greater the deterioration ofcolor appearance.

On the other hand, the test lights shown in FIGS. 28 to 32 representexamples where D_(uv) is shifted in a negative direction from −0.0100 to−0.0448. As described earlier, D_(uv)=−0.0448 is realized as a systemthat does not include a green phosphor. As shown, when D_(uv) is shiftedin the negative direction, it was found that the saturation of the 15color samples can be varied over a wider hue range as compared to thecase of the test light with D_(uv)=0.0001. It was also found that thesaturation of the 15 color samples can be varied relatively uniformly ascompared to the case of the test light with D_(uv)=0.0001. Moreover, itwas predicted that the color appearances of almost all of the 15 colorsamples with the exception of the blue region will appear vivid whenD_(uv) is shifted in the negative direction between a case whereillumination by the calculational reference lights is assumed and a casewhere illumination by the test lights shown in FIGS. 28 to 32 isassumed. Furthermore, a trend was also predicted in that the greater theshift of D_(uv) in the negative direction, the higher the saturation. Racalculated based on the test lights of FIGS. 28 to 32 was 89, 80, 71,61, and 56, respectively. According to currently prevailing belief, itwas predicted that the greater the shift of D_(uv) in the negativedirection, the further the deviation of color appearance from a case ofillumination with reference light and, therefore, the greater thedeterioration of color appearance.

[Summary of Examination of Calculation Regarding Saturation Control andD_(uv) Value]

From the examination of calculations thus far, the following waspredicted “based on currently prevailing wisdom”.

(1) Test light with a chromaticity point in a vicinity of D_(uv)=0.0000has a low degree of freedom with respect to varying saturation of the 15color samples. Specifically, it is difficult to simultaneously varysaturation of a large number of hues of the 15 high-chroma colorsamples, to relatively uniformly increase or decrease saturation of manyhues, and the like.

(2) When D_(uv) of test light is set to a positive value, saturation ofthe 15 color samples can be lowered relatively easily. The saturation ofthe 15 color samples can be lowered over a wider hue range and in arelatively uniform manner as compared to the case of the test light withD_(uv)=0.0000. Furthermore, the greater the shift of D_(uv) in thepositive direction, the lower the saturation. In addition, since Rafurther decreases, it was predicted that in visual experiments or thelike, the greater the shift of D_(uv) in the positive direction, thegreater the deviation of color appearance in a case of illumination bytest light from a case where an actual illuminated object or the like isilluminated by experimental reference light or experimentalpseudo-reference light and, therefore, the greater the deterioration ofcolor appearance.

(3) When D_(uv) is set to a negative value, saturation of the 15 colorsamples can be raised relatively easily. The saturation of the 15 colorsamples can be raised over a wider hue range and in a relatively uniformmanner as compared to the case of the test light with D_(uv)=0.0000.Furthermore, the greater the shift of D_(uv) in the negative direction,the higher the saturation. In addition, since Ra further decreases, itwas predicted that the greater the shift of D_(uv) in the negativedirection, the greater the deviation of color appearance in a case ofillumination by test light from a case where an actual illuminatedobject or the like is illuminated by experimental reference light orexperimental pseudo-reference light and, therefore, the greater thedeterioration of color appearance.

The above are predictions made “based on currently prevailing wisdom”from the examination of calculations thus far.

[Introduction of Quantitative Indices]

In the first to fifth inventions of the present invention, the followingquantitative indices were introduced in preparation of a detaileddiscussion regarding characteristics of a spectral power distribution ora color appearance itself, luminous efficacy of radiation, and the likeand in preparation of a detailed discussion regarding color appearance.

[Introduction of Quantitative Index Regarding Color Appearance]

First, it was decided that an a* value and a b* value of the 15 colorsamples in a CIE 1976 L*a*b* color space of test light as measured at aposition of an object when the object is illuminated by the test light(according to the illumination method of the fourth invention of thepresent invention) and/or test light when a light-emitting device emitsthe test light in a main radiant direction (according to thelight-emitting device of the first invention of the present invention)be respectively denoted by a*_(nSSL) and b*_(nSSL) (where n is a naturalnumber from 1 to 15), hue angles of the 15 color samples be respectivelydenoted by θ_(nSSL) (degrees) (where n is a natural number from 1 to15), an a* value and a b* value of the 15 color samples in a CIE 1976L*a*b* color space when mathematically assuming illumination bycalculational reference light that is selected according to a CCT of thetest light (black-body radiator when lower than 5000 K and CIE daylightwhen equal to or higher than 5000 K) be respectively denoted bya*_(nref) and b*_(nref) (where n is a natural number from 1 to 15), hueangles of the 15 color samples be respectively denoted by θ_(nref)(degrees) (where n is a natural number from 1 to 15), and an absolutevalue of respective differences in hue angles Δh_(n) (degrees) (where nis a natural number from 1 to 15) of the 15 Munsell renotation colorsamples when illuminated by the two lights be defined as|Δh _(n)|=|θ_(nSSL)−θ_(nref)|.That is, |Δh_(n)| involves “Δh₁, Δh₂, Δh₃, . . . and Δh₁₅”.

This was done because mathematically-predicted differences in hue anglesrelated to the 15 Munsell renotation color samples specially selected inthe first to fifth inventions of the present invention were consideredimportant indices for evaluating various objects or color appearances ofthe objects as a whole and realizing high visibility, good colorappearance of chromatic colors and improved feeling of brightness whenperforming visual experiments using test light and experimentalreference light or experimental pseudo-reference light.

In addition, each saturation differences ΔC_(n) (where n is a naturalnumber from 1 to 15) of the 15 Munsell renotation color samples whenassuming illumination by two lights, namely, test light andcalculational reference light, were respectively defined asΔC _(n)=√{(a* _(nSSL))²+(b* _(nSSL))²}−√{(a* _(nref))²+(b* _(nref))²}.

Furthermore, formula (1) below which represents an average saturationdifference of the 15 Munsell renotation color samples (hereinaftersometimes referred to as “SAT_(av)”) was also considered to be animportant index.

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 41} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3)\end{matrix}$

Moreover, if a maximum saturation difference value among the 15 Munsellrenotation color samples is denoted by ΔC_(max) and a minimum saturationdifference value among the 15 Munsell renotation color samples isdenoted by ΔC_(min), then |ΔC_(max)−ΔC_(min) representing a differencebetween the maximum saturation difference value and the minimumsaturation difference value (difference among differences betweenmaximum and minimum degrees of saturation) was also considered animportant index. This was done because various characteristics relatedto differences in saturation among the 15 Munsell renotation colorsamples specially selected in the first to fifth inventions of thepresent invention were considered important indices for evaluatingvarious objects or color appearances of the objects as a whole andrealizing a color appearance or an object appearance that is natural,vivid, highly visible, and comfortable when performing visualexperiments using test light and experimental reference light orexperimental pseudo-reference light.

[Introduction of Quantitative Index Regarding Spectral PowerDistribution]

In the first to fifth inventions of the present invention, the followingtwo quantitative indices were introduced in order to further discussradiometric properties and photometric properties of spectral powerdistributions. One is an index A_(cg) and the other is luminous efficacyof radiation K (lm/W).

The index A_(cg) is an attempt to describe a difference between a colorappearance by experimental reference light or experimentalpseudo-reference light and a color appearance by test light as aradiometric property and a photometric property of a spectral powerdistribution or a spectrum shape. As a result of various examinations,the index A_(cg) has been defined in the first to fifth inventions ofthe present invention as follows.

Let φ_(ref) (λ) and φ_(SSL) (λ) respectively denote spectral powerdistributions of calculational reference light and test light whichrepresent color stimuli that differ from one another when measuringlight emitted in a main radiant direction from a light-emitting device(according to the light-emitting device of the first invention of thepresent invention) or when measured at a position of an illuminatedobject (according to the illumination method of the fourth invention ofthe present invention), x (λ), y (λ), and z (λ) denote a color-matchingfunction, and (X_(ref), Y_(ref), Z_(ref)) and (X_(SSL), Y_(SSL),Z_(SSL)) respectively denote tristimulus values corresponding to thecalculational reference light and the test light. In this case, thefollowing is satisfied regarding the calculational reference light andthe test light, where k denotes a constant.Y _(ref) =k∫φ _(ref)(λ)·y(λ)dλY _(SSL) =k∫φ _(SSL)(λ)·y(λ)dλ

At this point, normalized spectral power distributions obtained bynormalizing the spectral power distributions of the calculationalreference light and the test light by their respective Y were defined asS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),and a difference between the normalized reference light spectral powerdistribution and the normalized test light spectral power distributionwas represented byΔS(λ)=S _(ref)(λ)−S _(SSL)(λ).Furthermore, at this point, the index A_(cg) was defined as follows.A _(og)=∫_(Λ1) ^(Λ2) ΔS(λ)dλ+∫ _(Λ2) ^(Λ3)(−ΔS(λ))dλ+∫ _(Λ3) ^(Λ4)ΔS(λ)dλ  [Expression 42]

Moreover, upper and lower limit wavelengths of the integrals wererespectively set to

Λ1=380 nm,

Λ2=495 nm, and

Λ3=590 nm.

In addition, Λ4 was defined divided into the following two cases. First,in the normalized test light spectral power distribution S_(SSL) (λ),when a wavelength which provides a longest wavelength local maximumvalue within 380 nm to 780 nm is denoted by λ_(R) (nm) and a spectralintensity of the wavelength λ_(R) (nm) is denoted by S_(SSL) (λ_(R)), awavelength which is on a longer wavelength-side of λ_(R) and which hasan intensity of S_(SSL) (λ_(R))/2 was adopted as Λ4. If no suchwavelength exists within a range up to 780 nm, then Λ4 was set to 780nm.

The index A_(cg) is used when a visible range related to radiations thatare color stimuli is roughly divided into a short wavelength range (orthe blue region including purple and the like), an intermediatewavelength range (the green region including yellow and the like), and along wavelength range (the red region including orange and the like) inorder to determine whether a concave and/or a convex shape of a spectrumexist at an appropriate intensity and at an appropriate position in anormalized test light spectral power distribution as compared to amathematically normalized reference light spectral power distribution.As illustrated in FIGS. 33 and 34, long wavelength integral rangesdiffer according to positions of a longest wavelength local maximumvalue. In addition, selections of calculational reference light differaccording to a CCT of test light. In the case of FIG. 33, since the CCTof the test light depicted by a solid line in FIG. 33 is equal to orhigher than 5000 K, CIE daylight is selected as the reference light asdepicted by a dotted line in FIG. 33. In the case of FIG. 34, since theCCT of the test light depicted by a solid line in FIG. 34 is lower than5000 K, black-body radiator is selected as the reference light asdepicted by a dotted line in FIG. 34. Moreover, shaded portions in thedrawings schematically represent integral ranges of the short wavelengthrange, the intermediate wavelength range, and the long wavelength range.

In the short wavelength range, a first term of A_(cg) (an integral of ΔS(λ)) is more likely to have a negative value when a spectrum intensityof the normalized test light spectral power distribution is higher thanthat of the mathematically normalized reference light spectral powerdistribution. In the intermediate wavelength range, conversely, a secondterm of A_(cg) (an integral of −ΔS (λ)) is more likely to have anegative value when a spectrum intensity of the normalized test lightspectral power distribution is lower than that of the normalizedreference light spectral power distribution. Furthermore, in the longwavelength range, a third term of A_(cg) (an integral of ΔS (λ)) is morelikely to have a negative value when a spectrum intensity of thenormalized test light spectral power distribution is higher than that ofthe normalized reference light spectral power distribution.

In addition, as described earlier, the calculational reference lightvaries according to the CCT of the test light. In other words,black-body radiator is used as the calculational reference light whenthe CCT of the test light is lower than 5000 K, and defined CIE daylightis used as the calculational reference light when the CCT of the testlight is equal to or higher than 5000 K. When deriving a value of theindex A_(cg), mathematically defined black-body radiator or CIE daylightwas used for φ_(ref) (λ), while a function used based on a simulation ora value actually measured in an experiment was used for φ_(SSL) (λ).

Furthermore, when measuring light emitted in a main radiant directionfrom a light-emitting device (according to the light-emitting device ofthe first invention of the present invention) or when evaluating thetest light spectral power distribution φ_(SSL) (λ) when measured at aposition of an illuminated object (according to the illumination methodof the present invention), the widely-used definition below was adoptedfor luminous efficacy of radiation K (lm/W).K=Km×[∫ ₃₈₀ ⁷⁸⁰{φ_(SSL)(λ)×V(λ)}dλ]/[·₃₈₀ ⁷⁸⁰φ_(SSL)(λ)dλ]  [Expression43]In the equation above,

K_(m): maximum luminous efficacy (lm/W),

V (λ): spectral luminous efficiency, and

λ: wavelength (nm).

The luminous efficacy of radiation K (lm/W) of the test light spectralpower distribution φ_(SSL) (λ) when measuring light emitted in a mainradiant direction from a light-emitting device (according to thelight-emitting device of the first invention of the present invention)or when measured at a position of an illuminated object (according tothe illumination method of the fourth invention of the presentinvention) is an amount that equals luminous efficacy of a source η(lm/W) when an efficiency of the spectral power distribution which isattributable to its shape and which is related to characteristics of allmaterials constituting the light-emitting device (for example,efficiencies such as internal quantum efficiency and light extractionefficiency of a semiconductor light-emitting element, internal quantumefficiency and external quantum efficiency of a phosphor, and lighttransmission characteristics of an encapsulant) is 100%.

[Details of Second Step]

In the first embodiment of the first to fifth inventions of the presentinvention, as described earlier, as the second step, prototypes of apackaged LED light source and a lighting fixture were made based on themathematically examined spectra (test lights). In addition, prototypesof a light source for light (experimental pseudo-reference light) with ahigh R_(a) and a high R_(i) and which produces a color appearance thatis close to that of calculational reference light as well as prototypesof a lighting fixture incorporating the light source were also made.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, as described earlier, as the secondstep, prototypes of a packaged LED light source and a lighting fixturethat does not include a control element were made based on themathematically examined spectra (test lights). In addition, prototypesof a light source for light (experimental pseudo-reference light) with ahigh R_(a) and a high R_(i) and which produces a color appearance thatis close to that of calculational reference light as well as prototypesof a lighting fixture incorporating the light source were also made.

Specifically, in the first to fifth inventions of the present invention,prototypes of a light source that excites a green phosphor and a redphosphor using a blue semiconductor light-emitting element, a lightsource that excites a yellow phosphor and a red phosphor using a bluesemiconductor light-emitting element, and a light source that excites ablue phosphor, a green phosphor, and a red phosphor using a purplesemiconductor light-emitting element were made and instrumentalized.

BAM or SBCA was used as the blue phosphor. BSS, β-SiAlON, or BSON wasused as the green phosphor. YAG was used as the yellow phosphor. CASONor SCASN was used as the red phosphor.

A normally practiced method was used when making packaged LEDprototypes. Specifically, a semiconductor light-emitting element (chip)was flip-chip-mounted on a ceramic package which incorporated metalwiring capable of providing electric contact. Next, a slurry created bymixing a phosphor to be used and a binder resin was arranged as aphosphor layer.

In the first embodiment of the first to fifth inventions of the presentinvention, after the packaged LEDs were prepared, the packaged LEDs wereused to create LED bulbs of MR16 Gu10, and MR16 Gu5.3. The LED bulbswere made into a type of a lighting fixture by building a drive circuitinto the LED bulbs and also mounting a reflecting mirror, a lens, andthe like to the LED bulbs. In addition, some commercially available LEDbulbs were also prepared. Furthermore, incandescent bulbs incorporatinga tungsten filament were also prepared to be used as experimentalreference light.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, after the packaged LEDs wereprepared, the packaged LEDs were used to create LED bulbs of MR16 Gu10,and MR16 Gu5.3. The LED bulbs were made into a type of a lightingfixture by building a drive circuit into the LED bulbs and also mountinga reflecting mirror that does not affect an intensity modulation onemission wavelength, a lens, and the like to the LED bulbs. In addition,some commercially available LED bulbs were also prepared. Furthermore,incandescent bulbs incorporating a tungsten filament were also preparedto be used as experimental reference light.

In addition, in the first to fifth inventions of the present invention,a large number of the LED bulbs were arranged to produce a lightingsystem for conducting comparative visual experiments. In this case, asystem capable of illumination by instantaneously switching among threekinds of bulbs was assembled. A type of drive power wire was dedicatedfor an incandescent bulb having a tungsten filament (experimentalreference light), and an adjustable transformer was arranged at asubsequent stage so that the CCT can be varied by boosting drive voltagefrom 110 V to 130 V relative to 100 V input voltage. Furthermore, tworemaining lines of the drive power wire were used for the LED bulbs, inwhich one system was used for experimental pseudo-reference light (LEDlight source) and the other for test light.

[Details of Third Step]

In the first to fifth inventions of the present invention, as the thirdstep, comparative visual experiment were conducted in which subjectswere asked to evaluate color appearances of a large number ofobservation objects while switching between experimental reference light(or experimental pseudo-reference light) and test light. The lightingsystem was installed in a dark room in order to remove disturbance. Inaddition, illuminance at the positions of the observation objects wasset approximately the same by varying the number of fixtures ofexperimental reference light (or experimental pseudo-reference light)and test light which were mounted to the lighting system. The experimentwas conducted within an illuminance range of approximately 150 lx toapproximately 5000 lx.

Illuminated objects and observed objects which were actually used willbe listed below. Due consideration was given to preparing chromaticobjects so that colors of all hues including purple, bluish purple,blue, greenish blue, green, yellowish green, yellow, reddish yellow,red, and reddish purple were represented. Achromatic objects such aswhite objects and black objects were also prepared. In addition, theseobjects were prepared in wide varieties and in large numbers includingstill objects, fresh flowers, food, clothing, and printed material.Furthermore, the skins of the subjects (Japanese) themselves were alsoincluded in the experiment as observation objects. Moreover, the colornames partially added to the object names listed below simply signifythat such objects will appear in such colors in ordinary environmentsand are not accurate representations of the colors.

White ceramic plate, white asparagus, white mushroom, white gerbera,white handkerchief, white dress shirt, white rice, sesame and salt,salted rice cracker

Purple fresh flower

Bluish purple cloth handkerchief, blue jeans, greenish blue towel Greenbell pepper, lettuce, shredded cabbage, broccoli, green lime, greenapple

Yellow banana, yellow bell pepper, greenish yellow lemon, yellow gerberafried egg

Orange orange, orange bell pepper, carrot

Red tomato, red apple, red bell pepper, red sausage, pickled plum Pinknecktie, pink gerbera, salmon broiled with salt

Russet necktie, beige work clothes, croquette, pork cutlet, burdock,cookie, chocolate peanut, woodenware

Skin of subjects (Japanese)

Newspaper, color printed matter including black letters on whitebackground (polychromatic), paperback, weekly magazine Color samples forexternal wall material (ALPOLIC manufactured by Mitsubishi Plastics,Inc; white, blue, green, yellow and red) Color checkers (Color checkerclassic manufactured. by X-Rite; total of 24 color samples including 18chromatic colors and six achromatic colors (one white, four grey, andone black)).

Moreover, names and Munsell notations of the respective color samples inthe color checker are as follows.

Name Munsell Notation Dark skin 3.05 YR 3.69/3.20 Light skin 2.2 YR6.47/4.10 Blue sky 4.3 PB 4.95/5.55 Foliage 6.65 GY 4.19/4.15 Blueflower 9.65 PB 5.47/6.70 Bluish green 2.5 BG 7/6 Orange 5 YR 6/11Purplish blue 7.5 PB 4/10.7 Moderate red 2.5 R 5/10 Purple 5 P 3/7Yellow green 5 GY 7.08/9.1 Orange yellow 10 YR 7/10.5 Blue 7.5 PB2.90/12.75 Green 0.1 G 5.38/9.65 Red 5 R 4/12 Yellow 5 Y 8/11.1 Magenta2.5 RP 5/12 Cyan 5 B 5/8 White N 9.5/ Neutral 8 N 8/ Neutral 6.5 N 6.5/Neutral 5 N 5/ Neutral 3.5 N 3.5/ Black N 2/

Moreover, it is not always self-evident that a correlation existsbetween color appearances of the various illuminated objects used in thecomparative visual experiments and the various mathematical indicesrelated to the color appearances of the 15 Munsell color samples used inthe calculations. Such a correlation is to be revealed through thevisual experiments.

The visual experiments were performed by the following procedure.

The prepared experimental reference light, experimental pseudo-referencelight, and test light were divided per CCT as measured at the positionof illuminated objects (according to the illumination method of thefourth invention of the present invention) or lights emitted in the mainradiant directions among the prepared experimental reference light,experimental pseudo-reference light, and test light were divided per CCT(according to the light-emitting device of the first invention of thepresent invention) into six experiments. Details are as follows.

TABLE 1 CCT classification in visual experiments Experiment CCT range(K) A 2500 or higher lower than 2600 B 2600 or higher lower than 2700 C2700 or higher lower than 2900 D 2900 or higher lower than 3250 E 3500or higher lower than 4100 F 5400 or higher lower than 5700

In each visual experiment, a same object was illuminated by switchingbetween experimental reference light (or experimental pseudo-referencelight) and test light, and subjects were asked to relatively judge whichlight was capable of realizing a color appearance or an objectappearance that is as natural, vivid, highly visible, and comfortable asthough perceived outdoors. The subjects were also asked the reasons fortheir judgment regarding which is superior or inferior.

[Details of Fourth Step, Experiment Result]

In the fourth step of the first embodiment of the first to fourthinventions of the present invention, results of comparative visualexperiments conducted in the third step using the prototypes of LEDlight sources/fixtures/systems made in the second step were compiled.

In the fourth step of the second embodiment of the first, second, fourthand fifth inventions of the present invention, results of comparativevisual experiments conducted in the third step using the prototypes ofLED light sources/fixtures/systems that do not include a control elementmade in the second step were compiled. Both results are the same.

Table 2 represents results corresponding to experiment A and Table 3represents results corresponding to experiment B. The same shall applythereafter, with Table 7 representing results corresponding toexperiment F. Regarding comprehensive evaluations of the test lightsrelative to the reference light shown in Tables 2 to 7, a comparableappearance is represented by a central “0”, an evaluation that the testlight is slightly favorable is represented by “1”, an evaluation thatthe test light is favorable is represented by “2”, an evaluation thatthe test light is more favorable is represented by “3”, an evaluationthat the test light is extremely favorable is represented by “4”, and anevaluation that the test light is dramatically favorable is representedby “5”. On the other hand, an evaluation that the test light is slightlyunfavorable is represented by “−1”, an evaluation that the test light isunfavorable is represented by “−2”, an evaluation that the test light ismore unfavorable is represented by “−3”, an evaluation that the testlight is extremely unfavorable is represented by “−4”, and an evaluationthat the test light is dramatically unfavorable is represented by “−5”.

In the fourth step, in particular, an attempt was made to extract aradiometric property and a photometric property of a spectral powerdistribution shared by the test light from an actually measured spectrumin a case where the color appearance of an illuminated object whenilluminated by the test light was judged to be more favorable than whenilluminated by experimental reference light or experimentalpseudo-reference light in a visual experiment. In other words, withrespect to numerical values of A_(cg), luminous efficacy of radiation K(lm/W), CCT (K), D_(uv), and the like, characteristics of light emittedin the main radiant direction from the light-emitting device (accordingto the light-emitting device of the first invention of the presentinvention) and a position of the illuminated object (according to theillumination method of the fourth invention of the present invention)were extracted. At the same time, differences between color appearancesof the 15 color samples when assuming illumination by calculationalreference lights and color appearances of the 15 color samples whenassuming a test light spectral power distribution when actuallymeasuring light emitted in the main radiant direction from thelight-emitting device (according to the light-emitting device of thefirst invention of the present invention) or a test light spectral powerdistribution actually measured at the position of the illuminated object(according to the illumination method of the fourth invention of thepresent invention) were also compiled using |Δh_(n)|, SAT_(av), ΔC_(n),and |ΔC_(max)−ΔC_(min)| as indices. Moreover, while values of |Δh_(n)|and ΔC_(n) vary when n is selected, in this case, maximum and minimumvalues are shown. These values are also described in Tables 2 to 7.Moreover, since it was found that, with respect to the color appearanceof the illuminated object, results of comprehensive evaluation by thesubjects were relatively dependent on D_(uv) values of test lightemitted in the main radiant direction from the light-emitting device(according to the light-emitting device of the first invention of thepresent invention) or test light at the position of the illuminatedobject (according to the illumination method of the fourth invention ofthe present invention), Tables 2 to 7 have been sorted in a descendingorder of D_(uv) values.

Overall, it was determined by the present experiment that the objectappearance or the color appearance of an object being illuminated bytest light is more favorable than when being illuminated by experimentalreference light if D_(uv) takes an appropriate negative value and theindex A_(cg) and the like are within appropriate ranges or if |Δh_(n)|,SAT_(av), ΔC_(n), |ΔC_(max)−ΔC_(min)|, and the like are withinappropriate ranges. This result was unexpected in view of “results basedon currently prevailing wisdom” described in step 1.

TABLE 2 Summary of Experiment A (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation ReferenceTungsten 2,589 −0.00023 0.20 0.02 0.07 0.30 −0.10 0.40 18.05 140 100 —light filament Incandescent bulb (110 V) Comparative Purple LED 2,559−0.00169 6.14 0.01 0.45 3.50 −2.04 5.54 −2.04 240 97 0 test light 1 BAMBSS CASON Test light 1 Purple LED 2,548 −0.00516 8.22 0.20 1.95 9.41−3.44 12.84 −32.01 235 94 1 SBCA β-SiAlON CASON Test light 2 Purple LED2,538 −0.01402 6.90 0.00 4.39 13.90 −0.83 14.73 −41.70 229 92 4 SBCAβ-SiAlON CASON

TABLE 3 Summary of Experiment B (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation ReferenceTungsten 2,679 −0.00010 0.10 0.00 0.03 0.14 −0.05 0.19 3.40 145 100 —light filament Incandescent bulb (120 V) Comparative Purple LED 2,631−0.00255 6.24 0.00 0.71 4.23 −1.91 6.14 20.42 239 97 0 test light 2 BAMBSS CASON Test light 3 Purple LED 2,672 −0.00464 7.02 0.08 1.32 6.08−1.85 7.93 −11.06 236 96 1 SBCA β-SiAlON CASON Test light 4 Purple LED2,636 −0.01299 8.32 0.04 3.50 13.41 −2.43 15.83 −63.83 229 95 4 SBCAβ-SiAlON CASON Test light 5 Purple LED 2,668 −0.01803 7.23 0.10 4.6814.47 −0.67 15.14 −114.08 222 91 5 SBCA β-SiAlON CASON Test light 6Purple LED 2,628 −0.02169 7.42 0.40 5.09 16.84 −0.96 17.81 −126.42 21690 4 SBCA β-SiAlON CASON

TABLE 4 Summary of Experiment C (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation Comparative BlueLED 2,811 0.01380 9.51 0.29 −6.42 −0.11 −18.50 18.39 142.46 322 91 −4test light 3 BSON SCASN Comparative Blue LED 2,788 0.00970 5.00 0.51−3.49 0.05 −11.04 11.10 102.87 309 94 −2 test light 4 BSON SCASNComparative Commercially 2,880 0.00819 5.78 0.29 −3.33 −0.07 −8.02 7.95211.76 294 92 −2 test light 5 available LED Comparative Blue LED 2,7230.00020 1.84 0.00 0.51 3.47 −2.37 5.84 15.58 299 94 0 test light 6 BSONSCASN Reference Tungsten 2,749 −0.00017 0.12 0.00 0.04 0.18 −0.08 0.2616.59 150 100 — light filament Incandescent bulb (130 V) ComparativePurple LED 2,703 −0.00331 6.26 0.08 0.91 4.76 −1.78 6.53 22.48 238 97 0test light 7 BAM BSS CASON Test light 7 Purple LED 2,784 −0.00446 6.300.06 1.17 5.46 −1.92 7.37 −13.19 235 96 1 BAM BSS CASON Test light 8Purple LED 2,761 −0.00561 7.16 0.07 1.48 6.60 −2.16 8.76 −46.26 232 96 1BAM BSS CASON Test light 9 Blue LED 2,751 −0.01060 5.22 0.28 2.79 8.47−2.02 10.49 −28.57 289 93 3 BSON SCASN Test light Purple LED 2,798−0.01991 6.11 0.06 4.25 13.37 −0.63 14.01 −141.79 221 91 5 10 SBCAβ-SiAlON CASON Test light Purple LED 2,803 −0.02141 7.56 0.30 4.82 14.26−0.84 15.10 −176.30 216 90 4 11 SBCA β-SiAlON CASON Test light Blue LED2,736 −0.02210 4.56 0.07 4.99 12.13 −0.97 13.11 −139.12 257 85 4 12 BSONSCASN Test light Blue LED 2,718 −0.02840 7.10 0.23 6.36 16.62 0.89 15.72−174.29 251 84 2 13 BSON SCASN Comparative Blue LED 2,711 −0.03880 7.830.84 7.42 20.26 0.49 19.77 −253.28 240 80 −1 test light 8 BSON SCASNComparative Blue LED 2,759 −0.04270 7.61 0.16 7.86 20.06 1.04 19.03−228.40 231 77 −2 test light 9 BSON SCASN Comparative Blue LED 2,792−0.04890 5.92 0.24 7.50 19.12 1.22 17.90 −267.67 227 70 −3 test lightBSON SCASN 10

TABLE 5 Summary of Experiment D (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation Comparative BlueLED 3,005 0.01411 18.54 0.18 −5.95 4.13 −13.83 17.96 197.80 376 69 −4test light YAG 11 CASON Pseudo- Purple LED 2,973 0.00064 3.48 0.02 −0.041.49 −1.48 2.98 31.87 245 97 — reference BAM BSS light CASON ComparativeBlue LED 2,911 −0.00667 18.39 0.62 0.82 14.09 −11.10 25.20 61.34 330 72−2 test light YAG 12 CASON Test light Purple LED 3,026 −0.00742 3.770.18 2.53 6.06 −0.15 6.21 −17.86 281 92 1 14 SBCA β-SiAlON CASONComparative Blue LED 3,056 −0.01276 16.81 0.95 1.79 16.35 −10.53 26.8825.24 319 74 −2 test light YAG 13 CASON Test light Purple LED 2,928−0.01742 5.87 0.33 4.15 10.17 0.10 10.07 −177.14 216 88 5 15 SBCAβ-SiAlON CASON Comparative Blue LED 3,249 −0.01831 15.98 1.15 2.37 17.15−10.01 27.16 −6.20 310 75 −2 test light YAG 14 CASON Test light PurpleLED 2,992 −0.02498 7.63 0.33 4.86 13.54 −1.11 14.65 −247.50 210 88 3 16SBCA β-SiAlON CASON Test light Purple LED 3,001 −0.02525 7.66 0.34 4.8813.55 −1.14 14.69 −253.58 209 88 2 17 SBCA β-SiAlON CASON

TABLE 6 Summary of Experiment E (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation Pseudo- PurpleLED 3,866 0.00006 4.76 0.05 0.52 3.37 −2.13 5.50 −6.84 249 94 —reference SBCA β-SiAlON light CASON Test light Purple LED 3,673 −0.013022.86 0.04 2.32 5.16 −0.20 5.36 −82.35 236 93 4 18 SBCA β-SiAlON CASONTest light Purple LED 4,072 −0.01666 1.97 0.10 2.69 4.63 0.60 4.03−116.16 230 89 5 19 SBCA β-SiAlON CASON Test light Purple LED 3,631−0.02102 3.29 0.11 3.38 6.72 0.53 6.19 −173.43 223 87 4 20 SBCA β-SiAlONCASON

TABLE 7 Summary of Experiment F (results of visual experiment andvarious indices)     Light-emitting element     CCT (K)       D_(uv)|Δh_(n)| maxi- mum value |Δh_(n)| mini- mum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra   Compre- hensive evaluation ComparativePurple LED 5,490 0.0073137 5.45 0.03 −0.07 2.20 −2.45 4.65 56.25 255 94−2 test light SBCA 15 β-SiAlON CASON Pseudo- Purple LED 5,451 −0.0029174.50 0.02 0.07 2.21 −3.05 5.26 94.78 275 96 — reference BAM BSS lightCASON Test light Purple LED 5,484 −0.005339 3.32 0.02 1.61 3.19 0.033.16 −84.44 234 92 1 21 SBCA β-SiAlON CASON Test light Purple LED 5,538−0.007788 2.95 0.10 1.91 3.94 0.58 3.36 −86.47 231 90 2 22 SBCA β-SiAlONCASON Test light Purple LED 5,661 −0.009926 3.32 0.27 2.17 4.70 0.913.80 −114.17 229 88 2 23 SBCA β-SiAlON CASON Test light Purple LED 5,577−0.012668 3.72 0.08 2.49 5.31 0.95 4.36 −136.35 226 86 4 24 SBCAβ-SiAlON CASON Test light Purple LED 5,504 −0.01499 4.05 0.07 2.76 5.790.99 4.81 −155.28 224 84 4 25 SBCA β-SiAlON CASON Test light Purple LED5,531 −0.017505 4.53 0.06 3.04 6.48 0.93 5.55 −173.79 222 82 5 26 SBCAβ-SiAlON CASON Test light Purple LED 5,650 −0.020101 5.14 0.13 3.34 7.340.79 6.56 −180.73 220 79 4 27 SBCA β-SiAlON CASON Test light Purple LED5,470 −0.026944 6.06 0.25 4.06 8.68 0.82 7.86 −239.07 214 73 2 28 SBCAβ-SiAlON CASON Test light Purple LED 5,577 −0.033351 6.98 0.17 4.7310.23 0.67 9.56 −322.02 205 66 1 29 SBCA β-SiAlON CASON ComparativePurple LED 5,681 −0.038497 7.53 0.04 5.26 11.36 0.51 10.86 −419.02 19461 −1 test light SBCA 16 β-SiAlON CASON Comparative Purple LED 5,509−0.043665 7.95 0.39 5.74 12.04 0.37 11.66 −486.05 189 56 −2 test lightSBCA 17 β-SiAlON CASON[Details of Fourth Step, Consideration]

Hereinafter, the experiment results will be considered. Moreover, thetest lights and comparative test lights in the tables may sometimes becollectively referred to as a “test light”.

1) When D_(uv) of test light is on positive side of experimentalreference light (or experimental pseudo-reference light)

Tables 4, 5, and 7 include results in which the D_(uv) of test light ison the positive side of experimental reference light (or experimentalpseudo-reference light). From these results, it is found that thegreater the positive value of the D_(uv) of the test light, the lessfavorable the color appearance or the object appearance of theilluminated object as judged by the subjects. A more specificdescription will be given below.

With respect to the appearance of an illuminated white object, thesubjects judged that the greater the positive value of D_(uv), the moreyellowish (greenish) the appearance and the greater a feeling ofstrangeness. With respect to the appearance of gray portions of theilluminated color checkers, the subjects judged that differences inlightness became less visible. Furthermore, the subjects pointed outthat characters in illuminated printed matter became more illegible.Moreover, with respect to the color appearances of various illuminatedchromatic colors, the subjects judged that the greater the positivevalue of the D_(uv) of the test light, the more unnatural and dull thecolor appearances as compared to when illuminated by experimentalreference light (or experimental pseudo-reference light). The subjectspointed out that the various illuminated exterior wall color sampleswere perceived as being extremely different from the same colors whenviewed outdoors, and their own skin colors also appeared unnatural andunhealthy. In addition, the subjects pointed out that differences incolor of petals of fresh flowers with similar and analogous colorsbecame less distinguishable and contours became less visible as comparedto when illuminated by experimental reference light.

Furthermore, it was found that these results were not noticeablydependent on the CCT of the test lights described in Tables 4, 5, and 7,and also were not noticeably dependent on the configuration of thelight-emitting elements (light-emitting materials) of the light-emittingdevice.

Since the greater the positive value of the D_(uv) of the test light,the lower the value of Ra as an overall trend, one could argue that someof the results described above were within a range predictable from thedetailed mathematical examination performed in step 1.

2) When D_(uv) of test light is on negative side of experimentalreference light (or experimental pseudo-reference light)

All of the Tables 2 to 7 include results in which the D_(uv) of testlight is on the negative side of experimental reference light (orexperimental pseudo-reference light). These results show that when theD_(uv) of the test light was in an appropriate negative range and thevarious indices in the tables were in appropriate ranges, the subjectsjudged the color appearance or the object appearance of the illuminatedobject to be favorable, more favorable, extremely favorable, ordramatically favorable. On the other hand, it is also shown that even ifthe D_(uv) of the test light was in a similar range, the colorappearance or the object appearance of the illuminated object was judgedto be unfavorable or slightly favorable when the various indices in thetables were not in appropriate ranges as shown in Tables 2 to 5.

Among the results described above, it was totally unexpected that thecolor appearance of an object illuminated by test light would be anatural and favorable color appearance and a favorable object appearanceas compared to being illuminated by experimental reference light (orexperimental pseudo-reference light) when the D_(uv) of the test lightwas in an appropriate negative range and the various indices in thetables were in appropriate ranges. Details of features pointed out bythe subjects were as follows.

With white objects, the subjects judged that yellowness (greenness) haddecreased and the objects appeared slightly white, white, more white,extremely white, or dramatically white in comparison to beingilluminated by experimental reference light (or experimentalpseudo-reference light) when the D_(uv) of the test light was in anappropriate negative range and the various indices in the tables were inappropriate ranges. It was also pointed out that the closer to anoptimum range, the more natural and the more favorable the appearance.This was a totally unexpected result.

Furthermore, with gray portions of the color checkers, the subjectsjudged that differences in lightness had slightly increased, increased,further increased, extremely increased, or dramatically increased incomparison to being illuminated by experimental reference light (orexperimental pseudo-reference light) when the D_(uv) of the test lightwas in an appropriate negative range and the various indices in thetables were in appropriate ranges. The subjects also pointed out thatthe closer to an optimum range, the more natural and the higher thevisibility of the appearance. This was a totally unexpected result.

In addition, with contours of achromatic color samples, the subjectsjudged that clearness had slightly increased, increased, furtherincreased, extremely increased, or dramatically increased in comparisonto being illuminated by experimental reference light (or experimentalpseudo-reference light) when the D_(uv) of the test light was in anappropriate negative range and the various indices in the tables were inappropriate ranges. The subjects also pointed out that the closer to anoptimum range, the more natural and the higher the visibility of theappearance. This was a totally unexpected result.

Furthermore, with characters in printed matter, the subjects judged thatlegibility had slightly increased, increased, further increased,extremely increased, or dramatically increased in comparison to beingilluminated by experimental reference light (or experimentalpseudo-reference light) when the D_(uv) of the test light was in anappropriate negative range and the various indices in the tables were inappropriate ranges. The subjects also pointed out that the closer to anoptimum range, the more natural and the higher the legibility of theappearance of characters. This was a totally unexpected result.

In addition, with the illuminated objects in various chromatic colors,the subjects judged that the color appearances of the illuminatedobjects had a slightly natural vividness, a natural vividness, a furthernatural vividness, an extremely natural vividness, or a dramaticallynatural vividness in comparison to being illuminated by experimentalreference light (or experimental pseudo-reference light) when the D_(uv)of the test light was in an appropriate negative range and the variousindices in the tables were in appropriate ranges. The subjects alsopointed out that the closer to an optimum range, the more natural andfavorable the color appearance. This was a totally unexpected result.

Furthermore, with the various exterior wall color samples, the subjectsjudged that the color appearances of the color samples were slightlyclose, close, further close, extremely close, or dramatically close totheir memories when seeing the color samples outdoors in comparison tobeing illuminated by experimental reference light (or experimentalpseudo-reference light) when the D_(uv) of the test light was in anappropriate negative range and the various indices in the tables were inappropriate ranges. The subjects also pointed out that the closer to anoptimum range, the more natural and favorable the color appearance,which more closely resembled their memories when seeing the colorsamples outdoors. This was a totally unexpected result.

In addition, with the color appearances of the skin of the subjectsthemselves (Japanese), the subjects judged that their skin appearedslightly natural, natural, further natural, extremely natural, ordramatically natural in comparison to being illuminated by experimentalreference light (or experimental pseudo-reference light) when the D_(uv)of the test light was in an appropriate negative range and the variousindices in the tables were in appropriate ranges. The subjects alsopointed out that the closer to an optimum range, the more natural,healthy, and favorable the color appearance. This was a totallyunexpected result.

Furthermore, with differences in colors of petals of fresh flowers withsimilar and analogous colors, the subjects judged that the differencesbecame slightly distinguishable, distinguishable, furtherdistinguishable, extremely distinguishable, or dramaticallydistinguishable in comparison to being illuminated by experimentalreference light (or experimental pseudo-reference light) when the D_(uv)of the test light was in an appropriate negative range and the variousindices in the tables were in appropriate ranges. The subjects alsopointed out that the greater the negative value of D_(uv) relative to anappropriate upper limit within the experiment range, the greater thedistinguishability. This was a totally unexpected result.

In addition, with various illuminated objects, the subjects judged thatcontours appeared slightly clear, clear, further clear, extremely clear,or dramatically clear in comparison to being illuminated by experimentalreference light (or experimental pseudo-reference light) when the D_(uv)of the test light was in an appropriate negative range and the variousindices in the tables were in appropriate ranges. The subjects alsopointed out that the greater the negative value of D_(uv) relative to anappropriate upper limit within the experiment range, the clearer theappearance of the contours. This was a totally unexpected result.

Particularly since the greater the negative value of the D_(uv) of thetest light, the lower the value of Ra as an overall trend, one couldargue that these results were totally unexpected from the detailedmathematical examination performed in step 1. As shown in Tables 2 to 7,purely focusing on Ra values reveal that, for example, Ra of test lightscomprehensively judged to be “dramatically favorable” ranged from around82 and 91 despite the fact that there were a large number of test lightswith Ra of 95 or higher. In addition, the comparative visual experimentswere performed beyond the D_(uv) range described in ANSI C78.377-2008.Therefore, one can argue that the results described above represent anovel discovery of a perceptually favorable region related to the colorappearance of an illuminated object outside of a current common-senserecommended chromaticity range.

Meanwhile, with the light-emitting device according to the firstinvention of the present invention, it was shown that in order to obtainsuch perceptions, the indices A_(cg) described in Tables 2 to 7 must bewithin appropriate ranges in addition to D_(uv). In addition, it wasrevealed that the various indices, namely, the luminous efficacy ofradiation K (lm/W), |Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)|are favorably within appropriate ranges. This requirement is the samefor the method for designing the light-emitting device according to thesecond invention of the present invention, and the method for drivingthe light-emitting device according to the third invention. Thisrequirement is also the same for the method for manufacturing thelight-emitting device according to the second embodiment of the fifthinvention of the present invention.

Firstly, results of the test lights judged to be favorable in the visualexperiments revealed the following with respect to D_(uv) and the indexA_(cg).

First, D_(uv) was as considered heretofore and was −0.0040 or lower,slightly favorably −0.0042 or lower, favorably −0.0070 or lower, morefavorably −0.0100 or lower, extremely favorably −0.0120 or lower, anddramatically favorably −0.0160 or lower.

In addition, D_(uv) in the first to fifth inventions of the presentinvention was −0.0350 or higher, slightly favorably −0.0340 or higher,favorably −0.0290 or higher, more favorably −0.0250 or higher, extremelyfavorably −0.0230 or higher, and dramatically favorably −0.0200 orhigher.

Furthermore, from results shown in Tables 2 to 7, A_(cg) in spectralpower distributions produced by the light-emitting device according tothe first invention of the present invention was −10 or lower and −360or higher. Although a precise definition of A_(cg) is as describedearlier, a rough physical meaning or a clear interpretation thereof isas follows. “A_(cg) assumes a negative value in an appropriate range”means that there are appropriate existence of a concave and/or a convexshape in a normalized test light spectral power distribution, andradiant flux intensity of the normalized test light spectral powerdistribution tends to be higher than that of a mathematical normalizedreference light spectral power distribution in a short wavelength rangebetween 380 nm and 495 nm, and/or radiant flux intensity of thenormalized test light spectral power distribution tends to be lower thanthat of a mathematical normalized reference light spectral powerdistribution in an intermediate wavelength range between 495 nm and 590nm, and/or radiant flux intensity of the normalized test light spectralpower distribution tends to be higher than that of a mathematicalnormalized reference light spectral power distribution in a longwavelength range between 590 nm and Λ4. Based on the above, it isunderstood that a favorable color appearance or a favorable objectappearance was produced when A_(cg) is quantitatively −10 or lower and−360 or higher.

A_(cg) as derived from a spectral power distribution of light emitted ina main radiant direction from the light-emitting device according to thefirst invention of the present invention was −10 or lower, slightlyfavorably −11 or lower, more favorably −28 or lower, extremely favorably−41 or lower, and dramatically favorably −114 or lower.

In addition, A_(cg) as derived from a spectral power distribution oflight emitted in a main radiant direction from the light-emitting deviceaccording to the first invention of the present invention was −360 orhigher, slightly favorably −330 or higher, favorably −260 or higher,extremely favorably −181 or higher, and dramatically favorably −178 orhigher.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of A_(cg) withinfavorable experiment results under examination was −322 or higher and−12 or lower.

Furthermore, while the first to fifth inventions of the presentinvention aimed for the realization of test light with favorable colorappearance and high efficiency, results regarding luminous efficacy ofradiation K were as follows.

The luminous efficacy of radiation of the spectral power distributionproduced by the light-emitting device according to the first inventionof the present invention favorably ranged from 180 (lm/W) to 320 (lm/W)and was higher by approximately 20% or more than 150 (lm/W) which is avalue of an ordinary incandescent bulb or the like. The reason for thisis believed to be that radiation from the semiconductor light-emittingelement and radiation from the phosphor were internal. The reason forthis is also believed to be that an appropriate concave and/or convexshape was present at an appropriate position in the spectral powerdistributions with respect to a relationship with V (λ). From theperspective of achieving a balance with color appearance, the luminousefficacy of radiation as obtained from a spectral power distribution oflight emitted in a main radiant direction by the light-emitting deviceaccording to the first invention of the present invention favorablyranged as described below.

Although the luminous efficacy of radiation K produced by thelight-emitting device according to the first invention of the presentinvention was preferably 180 (lm/W) or higher, the luminous efficacy ofradiation K was slightly favorably 205 (lm/W) or higher, favorably 208(lm/W) or higher, and extremely favorably 215 (lm/W) or higher. On theother hand, while, ideally, the higher the luminous efficacy ofradiation K, the better, the luminous efficacy of radiation K in thefirst to fifth inventions of the present invention was preferably 320(lm/W) or lower. In consideration of achieving a balance with colorappearance, the luminous efficacy of radiation K was slightly favorably282 (lm/W) or lower, favorably 232 (lm/W) or lower, and dramaticallyfavorably 231 (lm/W) of lower.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of K within favorableexperiment results under examination was 206 (lm/W) or higher and 288(lm/W) or lower.

Thirdly, when considering the characteristics of |Δh_(n)|, SAT_(av)ΔC_(n), and |ΔC_(max)−ΔC_(min)|, it was found that the following trendsexist. Specifically, test lights which produced a favorable colorappearance or a favorable object appearance had the followingcharacteristics with respect to the color appearance of the 15 colorsamples when illumination by calculational reference light is assumedand the color appearance of the 15 color samples when illumination by anactually measured test light spectral power distribution is assumed.

The difference in hue angles (|Δh_(n)|) of the 15 color samples betweenillumination by test lights and illumination by calculational referencelight is relatively small, and an average saturation, SAT_(av), of the15 color samples when illuminated by the test lights had increased in anappropriate range as compared to that when illuminated by thecalculational reference light. Moreover, in addition to the averagevalues, individual saturations (ΔC_(n)) of the 15 color samples alsoshow that none of the respective ΔC_(n) of the 15 color samples whenilluminated by the test lights was excessively lower or higher than thesame values when illuminated by the calculational reference light andwere all in appropriate ranges. As a result, the difference amongdifferences between maximum and minimum degrees of saturation|ΔC_(max)−ΔC_(min)| was narrow in an appropriate range. When furthersimplified, it is inferable that an ideal case features smalldifferences in hue angles among the hues of all 15 color samples and arelatively uniform increase in saturation of the 15 color samples withinappropriate ranges when assuming illumination by test light as comparedto when assuming illumination of the 15 color samples by referencelight.

A solid line in FIG. 35 represents a normalized test light spectralpower distribution of the test light 5 judged to be “dramaticallyfavorable” in the comprehensive judgment shown in Table 3. In addition,a dotted line in FIG. 35 represents a normalized spectral powerdistribution of calculational reference light (black-body radiator)calculated based on a CCT of the test light. On the other hand, FIG. 36represents a CIELAB plot related to color appearances of the 15 colorsamples when assuming illumination by the test light 5 (solid line) andassuming illumination by the calculational reference light (black-bodyradiator) (dotted line). Moreover, while a direction perpendicular tothe plane of paper represents lightness, only a* and b* axes wereplotted for the sake of convenience.

Furthermore, FIGS. 37 and 38 summarize results of test light 15 judgedto be “dramatically favorable” in the comprehensive judgment shown inTable 5 in a similar manner to that described above, and FIGS. 39 and 40summarize results of test light 19 judged to be “dramatically favorable”in the comprehensive judgment shown in Table 6 in a similar manner tothat described above.

In this manner, it is shown that when a favorable color appearance or afavorable object appearance is obtained in the visual experiments,differences in hue angles among the hues of all 15 color samples aresmall and saturation of the 15 color samples increase relativelyuniformly within appropriate ranges when assuming illumination by thetest light as compared to when assuming illumination of the 15 colorsamples by the reference light. It is also shown that, from thisperspective, a CCT in a vicinity of 4000 K is favorable.

On the other hand, even if D_(uv) has a negative value in an appropriaterange, for example, the comparative test light 14 with D_(uv)≅−0.01831in Table 5 is judged in the visual experiments to have an unfavorableappearance created by the test lights. This is conceivably due to thefact that characteristics of the index A_(cg) were not appropriate.FIGS. 41 and 42 represent a result of a CIELAB plot performed withrespect to a normalized spectral power distribution and colorappearances of the 15 color samples for the comparative test light 14 ina similar manner to FIGS. 35, 36, and the like. As is apparent fromFIGS. 41 and 42, there is a large difference in hue angles among severalhues of the 15 color samples and saturation of the 15 color samples varyin an extremely non-uniform manner when comparing a case whereillumination of the 15 color samples by the reference light is assumedwith a case where illumination by the test lights is assumed.

The results of the visual experiments and the consideration thereof showthat the respective quantitative indices favorably fall within thefollowing ranges.

As described earlier, D_(uv) in the light-emitting device according tothe first invention of the present invention was −0.0040 or lower,slightly favorably −0.0042 or lower, favorably −0.0070 or lower, morefavorably −0.0100 or lower, extremely favorably −0.0120 or lower, anddramatically favorably −0.0160 or lower.

In addition, D_(uv) in the light-emitting device according to the firstinvention of the present invention was −0.0350 or higher, slightlyfavorably −0.0340 or higher, favorably −0.0290 or higher, more favorably−0.0250 or higher, extremely favorably −0.0230 or higher, anddramatically favorably −0.0200 or higher.

Each |Δh_(n)| in the light-emitting device according to the firstinvention of the present invention was preferably 9.0 or lower,extremely favorably 8.4 or lower, and dramatically favorably 7.3 orlower. In addition, it is conceivable that a lower |Δh_(n)| is morefavorable and that each |Δh_(n)| is more dramatically favorably 6.0 orlower, further dramatically favorably 5.0 or lower, and particularlydramatically favorably 4.0 or lower.

Moreover, each |Δh_(n)| in the light-emitting device according to thefirst invention of the present invention was preferably 0 or higher anda minimum value thereof during the visual experiments was 0.0029.Furthermore, an examination performed using actual test light during thevisual experiments revealed that a favorable range of each |Δh_(n)|within favorable experiment results under examination was 8.3 or lowerand 0.003 or higher.

SAT_(av) in the light-emitting device according to the first inventionof the present invention was preferably 1.0 or higher, slightlyfavorably 1.1 or higher, favorably 1.9 or higher, extremely favorably2.3 or higher, and dramatically favorably 2.6 or higher; and

preferably 7.0 or lower, favorably 6.4 or lower, extremely favorably 5.1or lower, and dramatically favorably 4.7 or lower.

Furthermore, an examination performed using actual test light during thevisual experiments revealed that a favorable range of the above indexwithin favorable experiment results under examination was 1.2 or higherand 6.3 or lower.

Each ΔC_(n) in the light-emitting device according to the firstinvention of the present invention was preferably −3.8 or higher,slightly favorably −3.5 or higher, extremely favorably −2.5 or higher,and dramatically favorably −0.7 or higher.

In addition, each ΔC_(n) in the light-emitting device according to thefirst invention of the present invention was preferably 18.6 or lower,favorably 17.0 or lower, and dramatically favorably 15.0 or lower.

Furthermore, an examination performed using actual test light during thevisual experiments revealed that a favorable range of each ΔC_(n) withinfavorable experiment results under examination was −3.4 or higher and16.8 or lower.

While |ΔC_(max)−ΔC_(min)| in the light-emitting device according to thefirst invention of the present invention was preferably 19.6 or lower,|ΔC_(max)−ΔC_(min)| was extremely favorably 17.9 or lower, anddramatically favorably 15.2 or lower. In addition, it is conceivablethat a lower |ΔC_(max)−ΔC_(min)| is more favorable and that|ΔC_(max)−ΔC_(min)| is further dramatically favorably 14.0 or lower andextremely dramatically favorably 13.0 or lower.

Moreover, |ΔC_(max)−ΔC_(min)| in the light-emitting device according tothe first invention of the present invention was preferably 2.8 orhigher and a minimum value thereof during the visual experiments was3.16. Moreover, an examination performed using actual test light duringthe visual experiments revealed that a favorable range of|ΔC_(max)−ΔC_(min)| within favorable experiment results underexamination is 3.2 or higher and 17.8 or lower.

Fourthly, the following findings were made regarding a CCT in thelight-emitting device according to the first invention of the presentinvention. In order to have the various indices, namely, |Δh_(n)|SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| assume more appropriate valueswhich were judged as being favorable in the comparative visualexperiments, CCT favorably assumed a value near 4000 K in thelight-emitting device according to the first invention of the presentinvention. This is conceivably due to a spectral power distribution oflight near 4000 K being hardly dependent on wavelength and isequi-energetic as also exhibited by reference light, and a test lightspectral power distribution in which a concave and/or a convex shape isformed can be easily realized with respect to reference light. In otherwords, even in comparison to CCTs in other cases, SAT_(av), can beincreased while keeping |Δh_(n)| and |ΔC_(max)−ΔC_(min)| at low levelsto easily control ΔC_(n) with respect to a large number of color samplesso that each ΔC_(n) assumes a desired value.

Therefore, a CCT in the light-emitting device according to the firstinvention of the present invention ranges slightly favorably from 1800 Kto 15000 K, favorably from 2000 K to 10000 K, more favorably from 2300 Kto 7000 K, extremely favorably from 2600 K to 6600 K, dramaticallyfavorably from 2900 K to 5800 K, and most favorably from 3400 K to 5100K.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of a CCT withinfavorable experiment results under examination was 2550 (K) or higherand 5650 (K) or lower.

Each parameter related to the method for manufacturing thelight-emitting device according to the second embodiment of the fifthinvention of the present invention, and the method for designing thelight-emitting device according to the second embodiment of the secondinvention of the present invention are also the same as each parameterof the light-emitting device according to the second embodiment of thefirst invention of the present invention.

Furthermore, with the illumination method according to the fourthinvention of the present invention, it was shown that, in addition toD_(uv), the various indices described in Tables 2 to 7 or, in otherwords, |Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| must bewithin appropriate ranges in order to obtain such perceptions. Inaddition, it was found that the index A_(cg) and the luminous efficacyof radiation K (lm/W) are favorably within appropriate ranges.

In particular, from the results of the test lights judged to befavorable in the visual experiments, in consideration of thecharacteristics of |Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)|,it was found that the following trends exist. Specifically, test lightswhich produced a favorable color appearance or a favorable objectappearance had the following characteristics with respect to the colorappearance of the 15 color samples when illumination by calculationalreference light is assumed and the color appearance of the 15 colorsamples when illumination by an actually measured test light spectralpower distribution is assumed.

The difference in hue angles (|Δh_(n)|) of the 15 color samples betweenillumination by test lights and illumination by calculational referencelight is relatively small, and an average saturation, SAT_(av), of the15 color samples when illuminated by the test lights had increased in anappropriate range as compared to that when illuminated by thecalculational reference light. Moreover, in addition to the averagevalues, individual saturations (ΔC_(n)) of the 15 color samples alsoshow that none of the respective ΔC_(n) of the 15 color samples whenilluminated by the test lights was excessively lower or higher than thesame values when illuminated by the calculational reference light andwere all in appropriate ranges. As a result, the difference amongdifferences between maximum and minimum degrees of saturation|ΔC_(max)−ΔC_(min)| was narrow in an appropriate range. When furthersimplified, it is inferable that an ideal case features smalldifferences in hue angles among the hues of all 15 color samples and arelatively uniform increase in saturation of the 15 color samples withinappropriate ranges when assuming illumination by test light as comparedto when assuming illumination of the 15 color samples by referencelight.

A solid line in FIG. 35 represents a normalized test light spectralpower distribution of test light 5 judged to be “dramatically favorable”in the comprehensive judgment shown in Table 3. In addition, a dottedline in FIG. 35 represents a normalized spectral power distribution ofcalculational reference light (black-body radiator) calculated based ona CCT of the test light. On the other hand, FIG. 36 represents a CIELABplot related to color appearances of the 15 color samples when assumingillumination by the test light 5 (solid line) and assuming illuminationby the calculational reference light (black-body radiator) (dottedline). Moreover, while a direction perpendicular to the plane of paperrepresents lightness, only a* and b* axes were plotted for the sake ofconvenience.

Furthermore, FIGS. 37 and 38 summarize results of test light 15 judgedto be “dramatically favorable” in the comprehensive judgment shown inTable 5 in a similar manner to that described above, and FIGS. 39 and 40summarize results of test light 19 judged to be “dramatically favorable”in the comprehensive judgment shown in Table 6 in a similar manner tothat described above.

In this manner, it is shown that when a favorable color appearance or afavorable object appearance is obtained in the visual experiments,differences in hue angles among the hues of all 15 color samples aresmall and saturation of the 15 color samples increase relativelyuniformly within appropriate ranges when assuming illumination by thetest light as compared to when assuming illumination of the 15 colorsamples by the reference light. It is also shown that, from thisperspective, a CCT in a vicinity of 4000 K is favorable.

On the other hand, even if D_(uv) has a negative value in an appropriaterange, for example, comparative test light 14 with D_(uv)≅−0.01831 inTable 5 is judged in the visual experiments to have an unfavorableappearance created by the test lights. This is conceivably due to thefact that some characteristics among |Δh_(n)|, SAT_(av), ΔC_(n), and|ΔC_(max)−ΔC_(min)| were inappropriate. FIGS. 41 and 42 represent aresult of a CIELAB plot performed with respect to a normalized spectralpower distribution and color appearances of the 15 color samples for thecomparative test light 14 in a similar manner to FIGS. 35, 36, and thelike. As is apparent from FIGS. 41 and 42, there is a large differencein hue angles among several hues of the 15 color samples and saturationof the 15 color samples vary in an extremely non-uniform manner whencomparing a case where illumination of the 15 color samples by thereference light is assumed with a case where illumination by the testlights is assumed.

The results of the visual experiments and the consideration thereof showthat the respective quantitative indices favorably fall within thefollowing ranges.

D_(uv) in the illumination method according to the fourth invention ofthe present invention was −0.0040 or lower, slightly favorably −0.0042or lower, favorably −0.0070 or lower, more favorably −0.0100 or lower,extremely favorably −0.0120 or lower, and dramatically favorably −0.0160or lower.

In addition, D_(uv) in the illumination method according to the fourthinvention of the present invention was −0.0350 or higher, slightlyfavorably −0.0340 or higher, favorably −0.0290 or higher, more favorably−0.0250 or higher, extremely favorably −0.0230 or higher, anddramatically favorably −0.0200 or higher.

Each |Δh_(n)| in the illumination method according to the fourthinvention of the present invention was 9.0 or lower, extremely favorably8.4 or lower, and dramatically favorably 7.3 or lower. In addition, itis conceivable that a lower |Δh_(u)| is more favorable and that each|Δh_(n)| is more dramatically favorably 6.0 or lower, furtherdramatically favorably 5.0 or lower, and particularly dramaticallyfavorably 4.0 or lower.

Moreover, each |Δh_(n)| in the illumination method according to thefourth invention of the present invention was 0 or higher and a minimumvalue thereof during the visual experiments was 0.0029. Furthermore, anexamination performed using actual test light during the visualexperiments revealed that a favorable range of each |Δh_(n)| withinfavorable experiment results under examination was 8.3 or lower and0.003 or higher.

SAT_(av) in the illumination method according to the fourth invention ofthe present invention was 1.0 or higher, slightly favorably 1.1 orhigher, favorably 1.9 or higher, extremely favorably 2.3 or higher, anddramatically favorably 2.6 or higher; and

7.0 or lower, favorably 6.4 or lower, extremely favorably 5.1 or lower,and dramatically favorably 4.7 or lower.

Furthermore, an examination performed using actual test light during thevisual experiments revealed that a favorable range of the above indexwithin favorable experiment results under examination was 1.2 or higherand 6.3 or lower.

Each ΔC_(n) in the illumination method according to the fourth inventionof the present invention was −3.8 or higher, slightly favorably −3.5 orhigher, extremely favorably −2.5 or higher, and dramatically favorably−0.7 or higher.

In addition, each ΔC_(n) in the illumination method according to thefourth invention of the present invention was 18.6 or lower, extremelyfavorably 17.0 or lower, and dramatically favorably 15.0 or lower.Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of each ΔC_(n) withinfavorable experiment results under examination was −3.4 or higher and16.8 or lower.

While |ΔC_(max)−ΔC_(min)| in the illumination method according to thefourth invention of the present invention was 19.6 or lower, extremelyfavorably 17.9 or lower, and dramatically favorably 15.2 or lower. Inaddition, it is conceivable that a lower |ΔC_(max)−ΔC_(min)| is morefavorable and that |ΔC_(max)−ΔC_(min)| is more dramatically favorably14.0 or lower and extremely dramatically favorably 13.0 or lower.

Moreover, |ΔC_(max)−ΔC_(min)| in the illumination method according tothe fourth invention of the present invention was 2.8 or higher, and aminimum value thereof during the visual experiments was 3.16.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of|ΔC_(max)−ΔC_(min)| within favorable experiment results underexamination was 3.2 or higher and 17.8 or lower.

Meanwhile, an attempt was made using Tables 2 to 7 to have a radiometricproperty and a photometric property of a test light spectral powerdistribution represent characteristics associated with test lights whichhad been comprehensively judged to have favorable characteristics in thevisual experiments.

Again, D_(uv) was as considered heretofore and was −0.0040 or lower,slightly favorably −0.0042 or lower, favorably −0.0070 or lower, morefavorably −0.0100 or lower, extremely favorably −0.0120 or lower, anddramatically favorably −0.0160 or lower.

In addition, D_(uv) in the illumination method according to the first tofifth inventions of the present invention was −0.0350 or higher,slightly favorably −0.0340 or higher, favorably −0.0290 or higher, morefavorably −0.0250 or higher, extremely favorably −0.0230 or higher, anddramatically favorably −0.0200 or higher.

On the other hand, the following observation was made regarding theindex A_(cg).

From results shown in Tables 2 to 7, A_(cg) in favorable spectral powerdistributions in the illumination method according to the fourthinvention of the present invention was −10 or lower and −360 or higher.Although a precise definition of A_(cg) is as described earlier, a roughphysical meaning or a clear interpretation thereof is as follows.“A_(cg) assumes a negative value in an appropriate range” means thatthere are appropriate existence of a concave and/or a convex shape in anormalized test light spectral power distribution, and radiant fluxintensity of the normalized test light spectral power distribution tendsto be higher than that of a mathematical normalized reference lightspectral power distribution in a short wavelength range between 380 nmand 495 nm, and/or radiant flux intensity of the normalized test lightspectral power distribution tends to be lower than that of amathematical normalized reference light spectral power distribution inan intermediate wavelength range between 495 nm and 590 nm, and/orradiant flux intensity of the normalized test light spectral powerdistribution tends to be higher than that of a mathematical normalizedreference light spectral power distribution in a long wavelength rangebetween 590 nm and Λ4. Since A_(cg) is a sum of respective elements inthe short wavelength range, the intermediate wavelength range, and thelong wavelength range, individual elements may not necessarily exhibitthe tendencies described above. Based on the above, it is understoodthat a favorable color appearance or a favorable object appearance wasproduced when A_(cg) is quantitatively −10 or lower and −360 or higher.

A_(cg) in the illumination method according to the fourth invention ofthe present invention was preferably −10 or lower, slightly favorably−11 or lower, more favorably −28 or lower, extremely favorably −41 orlower, and dramatically favorably −114 or lower.

In addition, in the illumination method according to the fourthinvention of the present invention, A_(cg) was preferably −360 orhigher, slightly favorably −330 or higher, favorably −260 or higher,extremely favorably −181 or higher, and dramatically favorably −178 orhigher.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of A_(cg) withinfavorable experiment results under examination was −322 or higher and−12 or lower.

Furthermore, while the fourth invention of the present invention aimedfor the realization of test light with favorable color appearance andhigh efficiency, results regarding luminous efficacy of radiation K wereas follows.

The luminous efficacy of radiation of the spectral power distributionsproduced by the illumination method according to the fourth invention ofthe present invention favorably ranged from 180 (lm/W) to 320 (lm/W) andwas higher by approximately 20% or more than 150 (lm/W) which is a valueof an ordinary incandescent bulb or the like. The reason for this isbelieved to be that radiation from the semiconductor light-emittingelement and radiation from the phosphor were internal. The reason forthis is also believed to be that an appropriate concave and/or convexshape was present at an appropriate position in the spectral powerdistributions with respect to a relationship with V (λ). From theperspective of achieving a balance with color appearance, the luminousefficacy of radiation in the illumination method according to thepresent invention favorably ranged as described below.

Although the luminous efficacy of radiation K in the illumination methodaccording to the fourth invention of the present invention waspreferably 180 (lm/W) or higher, the luminous efficacy of radiation Kwas slightly favorably 205 (lm/W) or higher, favorably 208 (lm/W) orhigher, and extremely favorably 215 (lm/W) or higher. On the other hand,while, ideally, the higher the luminous efficacy of radiation K, thebetter, the luminous efficacy of radiation K in the first to fifthinventions of the present invention was preferably 320 (lm/W) or lower.In consideration of achieving a balance with color appearance, theluminous efficacy of radiation K was slightly favorably 282 (lm/W) orlower, favorably 232 (lm/W) or lower, and dramatically favorably 231(lm/W) or lower.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of K within favorableexperiment results under examination was 206 (lm/W) or higher and 288(lm/W) or lower.

Furthermore, the following findings were made regarding a CCT in theillumination method according to the fourth invention of the presentinvention. In order to have the various indices, namely, |Δh_(n)|,SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| assume more appropriate valueswhich were judged as being favorable in the comparative visualexperiments, CCT favorably assumed a value near 4000 K in theillumination method according to the fourth invention of the presentinvention. This is conceivably due to a spectral power distribution oflight near 4000 K being hardly dependent on wavelength and isequi-energetic as also exhibited by reference light, and a test lightspectral power distribution in which a concave and/or a convex shape areformed can be easily realized with respect to reference light. In otherwords, even in comparison to CCTs in other cases, SAT_(av) can beincreased while keeping |Δh_(n)| and |ΔC_(max)−ΔC_(min)| at low levelsto easily control ΔC_(n) with respect to a large number of color samplesso that each ΔC_(n) assumes a desired value.

Therefore, a CCT in the illumination method according to the fourthinvention of the present invention ranges slightly favorably from 1800 Kto 15000 K, favorably from 2000 K to 10000 K, more favorably from 2300 Kto 7000 K, extremely favorably from 2600 K to 6600 K, dramaticallyfavorably from 2900 K to 5800 K, and most favorably from 3400 K to 5100K.

Moreover, an examination performed using actual test light during thevisual experiments revealed that a favorable range of a CCT withinfavorable experiment results under examination was 2550 (K) or higherand 5650 (K) or lower.

Details of Fifth Step (1): Examination with Light-Emitting DeviceIncluding a Plurality of Light Emitting Areas First Embodiment of FirstInvention of the Present Invention

In the fifth step, the inventor assumed that the light-emitting deviceincluded a plurality of light emitting areas, and examined how theappearance of colors of the light-emitting device change by adjustingthe radiant flux amount (luminous flux amount) of each light emittingarea. In other words, the characteristics of numeric values, such as theindex A_(cg), CCT (K), D_(uvSSL) and the luminous efficacy of radiationK (lm/W) of the light emitted from each light emitting area and thelight-emitting device in the main radiant direction, were extracted. Atthe same time, differences between color appearances of the 15 colorsamples when assuming illumination by calculational reference lights andcolor appearances of the 15 color samples when assuming a test lightspectral power distribution actually measured were also compiled using|Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| as indices.Moreover, while values of |Δh_(n)| and ΔC_(n) vary when n is selected,in this case, maximum and minimum values are shown. These values arealso described in Tables 8 to 12. The examination in the fifth step alsorepresents the examples and comparative examples according to the firstembodiment of the first to fourth inventions of the present invention.

In concrete terms, the inventor experimented on how φ_(SSL)(λ), which isthe sum of the spectral power distribution of the light emitted fromeach light emitting area in the main radiant direction, will change bychanging the luminous flux amount and/or radiant flux amount emittedfrom each light emitting area in the main radiant direction.

Details of Fifth Step (2): Examination Related to Control Element SecondEmbodiment of First Invention of the Present Invention

In the fifth step, the inventor introduced a control element, which wasproduced experimentally in the second step, to the LED lightsource/fixture/system which does not include a control element, andextracted the meteorological characteristics and photometriccharacteristics of the spectral power distribution of the lightirradiated from the light-emitting device which includes the controlelement, based on the measured spectrum. In other words, thecharacteristics of numeric values, such as the index A_(cg), theluminous efficacy of radiation K (lm/W), CCT (K) and D_(uv) of the lightemitted from each light emitting area and the light-emitting device inthe main radiant direction, were extracted. At the same time,differences between color appearances of the 15 color samples whenassuming illumination by calculational reference lights and colorappearances of the 15 color samples when assuming a test light spectralpower distribution actually measured were also compiled using |Δh_(n)|,SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(max)| as indices. Moreover, whilevalues of |Δh_(n)| and ΔC_(n) vary when n is selected, in this case,maximum and minimum values are shown. These values are also described inTables 17 and 18. The examination in the fifth step also represents theexamples and comparative examples according to the second embodiment ofthe first, second, fourth and fifth inventions of the present invention.

In concrete terms, the inventor experimented how Φ_(elm)(λ), which isthe spectral power distribution of the light emitted from thelight-emitting element in the main radiant direction, and φ_(SSL)(λ)which is the spectral power distribution of the light emitted from thelight-emitting device in the main radiant direction, will change if thecontrol element is included.

The experiments related to the present invention will now be described.

First Embodiment of First to Fourth Inventions of the Present InventionExample 1

A 5 mm diameter resin package in which two light emitting units exist,as shown in FIG. 43, is prepared. In the light emitting area 1, a bluesemiconductor light-emitting element, a green phosphor and a redphosphor are mounted and encapsulated. The blue semiconductorlight-emitting element in the light emitting area 1 constitutes a wiringof the packaged LED, so as to be one independent circuit configuration,and is connected to a power supply. In the light emitting area 2, on theother hand, a purple semiconductor light-emitting element, a bluephosphor, a green phosphor and a red phosphor are mounted andencapsulated. The purple semiconductor light-emitting element in thelight emitting area 2 constitutes a wiring of the packaged LED, so as tobe one independent circuit configuration, and is connected to anotherindependent power supply. In this way, current can be injectedindependently into the light emitting area 1 and the light emitting area2 respectively.

Next, if the current value of the current supplied to each lightemitting area of the packaged LED, which includes the light emittingarea 1 and the light emitting area 2, is appropriately adjusted, thenfive types of spectral power distributions shown in FIG. 44 to FIG. 48,irradiated onto the axis of the packaged LED for example, areimplemented. FIG. 44 is the case when the current is injected only intothe light emitting area 1, and the radiant flux ratio of the lightemitting area 1 and the light emitting area 2 is set to 3:0, and FIG. 48is a case when current is injected only into the light emitting area 2,and the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 0:3. FIG. 45 is a case when the radiant fluxratio of the light emitting area 1 and the light emitting area 2 is setto 2:1, FIG. 46 is a case when the radiant flux ratio is set to 1.5:1.5,and FIG. 47 is a case when the radiant flux ratio is set to 1:2. Bychanging the current that is injected into each area of the packaged LED10, the radiant flux irradiated from the packaged LED main body onto theaxis can be changed. The CIELAB plot in each drawing indicates the a*values and the b* values which are plotted: when 15 Munsell renotationcolor samples #01 to #15 are mathematically assumed as the illuminationobjects, and these illumination objects are illuminated using thispackaged LED; and when these illumination objects are illuminated by areference light derived from the correlated color temperature of thepackaged LED. Here, the drive point names A to E are assigned to theradiant flux of the light-emitting device in descending order ofcontribution of the radiant flux of the light emitting area 1. FIG. 49shows the chromaticity point at each of the drive points A to E on theCIE 1976 u′v′ chromaticity diagram. Table 8 shows the photometriccharacteristics and colormetric characteristics that are expected ateach drive point.

TABLE 8 Example 1     Drive Point       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 2,700 −0.01000 5.33 0.03 2.808.49 −2.61 11.10 −62.63 298 92 Point A Drive 2:1 3,392 −0.01399 3.440.23 2.51 5.58 −0.38 5.95 −108.18 267 91 Point B Drive 1.5:1.5 3,827−0.01420 3.27 0.14 2.34 4.39 0.03 4.36 −107.89 256 90 Point C Drive 1:24,325 −0.01346 3.05 0.08 2.17 3.81 0.23 3.57 −79.45 245 90 Point D Drive0:3 5,505 −0.00997 3.11 0.12 2.17 4.47 0.88 3.59 −105.25 229 89 Point E(*1) Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: purple semiconductor light-emitting element, bluephosphor, green phosphor and red phosphor

The spectral power distributions in FIG. 44 to FIG. 48, the CIELAB plotsin FIG. 44 and FIG. 48, the CIE 1976 u′v′ chromaticity diagram in FIG.49 and Table 8 clarify the following.

At the drive point A to the drive point E, and in areas between thesedrive points, a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects, as if the object areseen outdoors, can be implemented. For example, between the drive pointA and the drive point E, the correlated color temperature of thepackaged LED can be variable in a 2700K to 5505K range, and D_(uvSSL)can also be variable in the −0.00997 to −0.01420 range. Further, theaverage saturation difference of the 15 Munsell renotation color samplescan also be variable in a 2.80 to 2.17 range while implementing such anappearance of colors. Thus in the area where a preferable appearance ofcolors can be implemented, optimum illumination conditions can be easilyselected from the variable range in accordance with the age, gender orthe like of the user of the light-emitting device, or in accordance withspace, purpose or the like of the illumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 2

A 6 mm×9 mm ceramic package which includes a total of six light emittingunits, as shown in FIG. 50, is prepared. Here a blue semiconductorlight-emitting element, a green phosphor and a red phosphor are mountedand encapsulated in a light emitting area 1-1, a light emitting area 1-2and a light emitting area 1-3, whereby equivalent light emitting areasare formed. The semiconductor light-emitting elements in the lightemitting area 1-1, the light emitting area 1-2 and the light emittingarea 1-3 are connected in series, and connected to one independent powersupply. On the other hand, a purple semiconductor light-emittingelement, a blue phosphor, a green phosphor and a red phosphor aremounted and encapsulated in a light emitting area 2-1, a light emittingarea 2-2 and a light emitting area 2-3, whereby equivalent lightemitting areas are formed. The semiconductor light-emitting elements inthe light emitting area 2-1, the light emitting area 2-2 and the lightemitting area 2-3 are connected in series, and connected to anotherindependent power supply. Current can be injected into the lightemitting area 1 and the light emitting area 2 independently from eachother.

Then if the current value of the current injected into each lightemitting area of the packaged LED having the light emitting area 1 andthe light emitting area 2 is appropriately adjusted, the five types ofspectral power distributions shown in FIG. 51 to FIG. 55, irradiatedonto the axis of the packaged LED, for example, are implemented. FIG. 51is a case when current is injected only into the light emitting area 1and the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 3:0, and FIG. 55 is a case when current isinjected only into the light emitting area 2 and the radiant flux ratioof the light emitting area 1 and the light emitting area 2 is set to0:3. FIG. 52 is a case when the radiant flux ratio of the light emittingarea 1 and the light emitting area 2 is set to 2:1, FIG. 53 is a casewhen the radiant flux ratio is set to 1.5:1.5, and FIG. 54 is a casewhen the radiant flux ratio is set to 1:2. By changing the current to beinjected into each area of the packaged LED 20, the radiant fluxirradiated from the packaged LED main body onto the axis can be changed.The CIELAB plot in each drawing indicates the a* values and the b*values which are plotted respectively: when 15 Munsell renotation colorsamples #01 to #15 are mathematically assumed as the illuminationobjects, and these illumination objects are illuminated by the packagedLED; and when these illumination objects are illuminated by a referencelight derived from the correlated color temperature of the packaged LED.Here the drive point names A to E are assigned to the radiant flux ofthe light-emitting device in descending order of contribution of theradiant flux of the light emitting area 1. FIG. 56 shows thechromaticity point at each of the drive points A to E on the CIE 1976u′v′ chromaticity diagram. Table 9 shows the photometric characteristicsand colormetric characteristics that are expected at each drive point.

TABLE 9 Example 2     Drive Point       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 2,700 −0.00350 3.57 0.16 1.224.17 −2.80 6.97 6.32 308 94 Point A Drive 2:1 3,475 −0.00642 3.29 0.151.42 3.79 −0.93 4.72 −41.37 279 95 Point B Drive 1.5:1.5 3,931 −0.005853.44 0.10 1.26 3.19 −0.64 3.83 −27.96 268 95 Point C Drive 1:2 4,428−0.00439 3.50 0.05 1.05 2.58 −0.56 3.14 3.50 259 95 Point D Drive 0:35,506 0.00007 4.14 0.01 0.90 2.32 −0.80 3.13 −7.04 245 96 Point E (*1)Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: purple semiconductor light-emitting element, bluephosphor, green phosphor and red phosphor

The spectral power distributions in FIG. 51 to FIG. 55, the CIELAB plotsin FIG. 51 to FIG. 55, the CIE 1976 u′v′ chromaticity diagram in FIG. 56and Table 9 clarify the following.

At the drive point A, the drive point D and the drive point E, one orboth of D_(uvSSL) and A_(cg) is/are not in an appropriate range of thefirst embodiment of the first to fourth inventions of the presentinvention, but at the drive point B, the drive point C and in the areasbetween these drive points, a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects, as if theobjects are seen outdoors, can be implemented. For example, between thedrive point B and the drive point C, the correlated color temperature ofthe packaged LED can be variable in a 3475 K to 3931 K range, andD_(uvSSL) can also be variable in a −0.00642 to −0.00585 range, whileimplementing the above mentioned an appearance of colors. Further, theaverage saturation difference of the 15 Munsell renotation color samplescan also be variable in a 1.42 to 1.26 range. Thus in the area where apreferable appearance of colors can be implemented, optimum illuminationconditions can easily be selected from the variable range in accordancewith the age, gender or the like of the user of the light-emittingdevice, or in accordance with the space, purpose or the like of theillumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceif luminance is decreased then energy consumption can be suppressed,which is preferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 3

A light-emitting device, which is a 60 cm×120 cm illumination systemembedded in a ceiling, and includes 16 LED light bulbs (light emittingunits), is prepared, as shown in FIG. 57. Here each portion shaded bysolid lines is a light emitting area 1, where the same LED bulb ismounted to form an equivalent light emitting area. Each portion shadedby the dotted lines in FIG. 57 is a light emitting area 2, where thesame LED bulb is mounted to form an equivalent light emitting area. TheLED light bulbs mounted in the plurality of light emitting areas 1 areconnected in parallel, and connected to one independent power supply. Onthe other hand, the LED light bulbs mounted in the plurality of lightemitting areas 2 are connected in parallel and connected to anotherindependent power supply. The light emitting areas 1 and the lightemitting areas 2 can be driven independently. The LED light bulbconstituting the light emitting area 1 includes a blue semiconductorlight-emitting element, a green phosphor and a red phosphor, and the LEDlight bulb constituting the light emitting area 2 includes a bluesemiconductor light-emitting element, a green phosphor and a redphosphor which are adjusted differently.

Next, if the radiant fluxes of the LED light bulbs constituting thelight emitting area 1 and the light emitting area 2 are appropriatelyadjusted using dimming controllers connected to the independent powersupplies respectively, five types of spectral power distributions shownin FIG. 58 to FIG. 62 irradiated onto the central axis of theillumination system, for example, are implemented. FIG. 58 is a casewhen only the LED light bulbs constituting the light emitting areas 1are driven, and the radiant flux ratio of the light emitting area 1 andthe light emitting area 2 is set to 3:0, and FIG. 62 is a case when onlythe LED light bulbs constituting the light emitting areas 2 are drivenand the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 0:3. FIG. 59 is a case when the radiant fluxratio of the LED light bulbs constituting the light emitting area 1 andthe LED light emitting area 2 is set to 2:1. FIG. 60 is a case when theradiant flux ratio is set to 1.5:1.5, and FIG. 61 is a case when theradiant flux ratio is set to 1:2. By changing the driving conditions ofthe LED light values constituting each light emitting area, the radiantflux irradiated onto the central axis of the illumination system can bechanged.

The CIELAB plot in each drawing indicates the a* values and the b*values which are plotted respectively: when 15 Munsell renotation colorsamples #01 to #15 are mathematically assumed as the illuminationobjects and these illumination objects are illuminated using thisillumination system; and when these illumination objects are illuminatedby a reference light derived from the correlated color temperature ofthe light-emitting device of this illumination system. Here the drivepoint names A to E are assigned to the radiant flux of the illuminationsystem (light-emitting device) in descending order of contribution ofthe radiant flux of the LED light bulb constituting the light emittingarea 1. FIG. 63 shows the chromaticity points at each of the drivepoints A to E on the CIE 1976 u′v′ chromaticity diagram. Table 10 showsthe photometric characteristics and colormetric characteristics that areexpected at each drive point.

TABLE 10 Example 3     Drive Point       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 2,700 −0.03000 7.42 0.05 5.7817.43 −1.97 19.41 −218.09 270 83 Point A Drive 2:1 2,775 −0.01591 5.660.08 3.46 10.87 −1.91 12.78 −87.63 279 91 Point B Drive 1.5:1.5 2,806−0.00942 4.34 0.02 2.14 7.20 −1.92 9.12 −21.42 283 94 Point C Drive 1:22,833 −0.00325 3.92 0.13 0.64 3.28 −2.09 5.37 40.74 287 96 Point D Drive0:3 2,880 0.00819 5.78 0.29 −3.33 −0.07 −8.02 7.95 133.16 294 92 Point E(*1) Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: blue semiconductor light-emitting element, greenphosphor and red phosphor

The spectral power distributions in FIG. 58 to FIG. 62, the CIELAB plotsin FIG. 58 to FIG. 62, the CIE 1976 u′v′ chromaticity diagram in FIG. 63and Table 10 clarify the following.

At the drive point D and the drive point E, both D_(uvSSL) and A_(cg)are not in an appropriate range of the first embodiment of the first tofourth inventions of the present invention, but at the drive point A,the drive point B, the drive point C, and areas between and near thesedrive points, a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects, as of the objects areseen outdoors, can be implemented. For example, between the drive pointA and the drive point C, the correlated color temperature of theillumination system can be variable in a 2700 K to 2806 K range, andD_(uvSSL) can also be variable in a −0.03000 to −0.00942 range, whileimplementing the above mentioned appearance of colors. Further, theaverage saturation difference of the 15 Munsell renotation color samplescan also be variable in a 5.78 to 2.14 range. Thus in the area where apreferable appearance of colors can be implemented, optimum illuminationconditions can easily be selected from the variable range in accordancewith the age, gender or the like of the user of the light-emittingdevice, or in accordance with the space, purpose or the like of theillumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or the radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 4

A pair of ceramic packages, in which two 5 mm×5 mm ceramic packages,including one light emitting area respectively, are disposed close toeach other, is prepared as shown in FIG. 64. Here one of the ceramicpackages becomes the light emitting area 1 and the other becomes thelight emitting area 2. In the light emitting area 1, a purplesemiconductor light-emitting element, a blue phosphor, a green phosphorand a red phosphor are mounted and encapsulated. The light emitting area1 is connected to one independent power supply. In the light emittingarea 2, on the other hand, a blue semiconductor light-emitting elementand a yellow phosphor are mounted and encapsulated. The light emittingarea 2 is connected to another independent power supply. Thereby currentcan be injected into the light emitting area 1 and the light emittingarea 2 independently.

Next, if the current value of the current injected into each lightemitting area of the pair of packaged LEDs 40, which are the lightemitting area 1 and the light emitting area 2, is appropriatelyadjusted, five types of spectral power distributions shown in FIG. 65 toFIG. 69 irradiated onto the axis of the pair of packaged LEDs, forexample, are implemented. FIG. 65 is a case when current is injectedonly into the light emitting area 1 and the radiant flux ratio of thelight emitting area 1 and the light emitting area 2 is set to 9:0, andFIG. 69 is a case when current is injected only into the light emittingarea 2 and the radiant flux ratio of the light emitting area 1 and thelight emitting area 2 is set to 0:9. FIG. 66 is a case when the radiantflux ratio of the light emitting area 1 and the light emitting area 2 isset to 6:3, FIG. 67 is a case when the radiant flux ratio is set to4.5:4.5, and FIG. 68 is a case when the radiant flux ratio is set to1:8. By changing the current to be injected into each area of the pairof packaged LEDs 40, the radiant flux irradiated from the main body ofthe pair of packaged LEDs onto the central axis can be changed. TheCIELAB plot in each drawing indicates the a* values and the b* valueswhich are plotted respectively: when 15 Munsell renotation color samples#01 to #15 are mathematically assumed as the illumination objects, andthese illumination objects are illuminated by the pair of packaged LEDs;and when these illumination objects are illuminated by a reference lightderived from the correlated color temperature of the pair of packagedLEDs. Here the drive point names A to E are assigned to the radiant fluxof the light-emitting device in descending order of contribution of theradiant flux of the light emitting area 1. FIG. 70 shows thechromaticity points at each of the drive points A to E on the CIE 1976u′v′ chromaticity diagram. Table 11 shows the photometriccharacteristics and colormetric characteristics that are expected ateach drive point.

TABLE 11 Example 4       Example 4       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 9:0 5,500 −0.03029 5.94 0.19 4.479.11 1.32 7.79 −363.31 200 71 Point A Drive 6:3 5,889 −0.02163 4.50 0.112.57 5.90 −0.03 5.93 −211.44 219 80 Point B Drive 4.5:4.5 6,100 −0.016465.57 0.24 1.43 3.68 −1.35 5.03 −128.01 231 85 Point C Drive 1:8 6,644−0.00145 14.57 0.16 −1.97 4.99 −6.99 11.98 69.36 275 86 Point D Drive0:9 6,814 0.00382 18.10 0.31 −3.20 5.55 −9.51 15.06 116.79 294 81 PointE (*1) Light-emitting elements constituting each light emitting area(*2) Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: purplesemiconductor light-emitting element, blue phosphor, green phosphor andred phosphor; Light emitting area 2: blue semiconductor light-emittingelement and yellow phosphor

The spectral power distributions in FIG. 65 to FIG. 69, the CIELAB plotsin FIG. 65 to FIG. 69, the CIE 1976 u′v′ chromaticity diagram in FIG. 70and Table 11 clarify the following.

At the drive point A, the drive point D and the drive point E, one orboth of D_(uvSSL) and A_(cg) is/are not in an appropriate range of thefirst embodiment of the first to fourth inventions of the presentinvention, but at the drive point B, the drive point C and areas betweenand near these drive points, a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects, as if theobjects are seen outdoors, can be implemented. For example, between thedrive point B and the drive point C, the correlated color temperature asthe packaged LED can be variable in a 5889 K to 6100 K, and D_(uvSSL)can also be variable in a −0.02163 to −0.01646 range, while implementingthe above mentioned appearance of colors. Further, the averagesaturation difference of the 15 Munsell renotation color samples canalso be variable in a 2.57 to 1.43 range. Thus in the area where apreferable appearance of colors can be implemented, optimum illuminationconditions can easily by selected from the variable range in accordancewith the age, gender or the like of the user of the light-emittingdevice, or in accordance with the space, purpose or the like of theillumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Comparative Example 1

A resin packaged LED similar to Example 1 is prepared except for thefollowing difference. In the light emitting area 1, a blue semiconductorlight-emitting element, a green phosphor and a red phosphor are mountedand encapsulated, but unlike Example 1, the mixing ratio thereof ischanged so that the spectral power distribution, when power is suppliedonly to the light emitting area 1, becomes the same as the case of thedrive point E of Example 3. In the light emitting area 2, a bluesemiconductor light-emitting element and a yellow phosphor are mountedand encapsulated unlike Example 1, so that the spectral powerdistribution when power is supplied only to the light emitting area 2becomes the same as the case of the drive point E of Example 4.

Next, if the current value of current injected into each light emittingarea of the packaged LED having the light emitting area 1 and the lightemitting area 2 is appropriately adjusted, five types of spectral powerdistributions shown in FIG. 71 to FIG. 75 irradiated onto the axis ofthe packaged LED, for example, are implemented. FIG. 71 is a case whencurrent is injected only into the light emitting area 1 and the radiantflux ratio of the light emitting area 1 and the light emitting area 2 isset to 3:0, and FIG. 75 is a case when current is injected only into thelight emitting area 2 and the radiant flux ratio of the light emittingarea 1 and the light emitting area 2 is set to 0:3. FIG. 72 is a casewhen the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 2:1, FIG. 73 is a case when the radiant fluxratio is set to 1.5:1.5, and FIG. 74 is a case when the radiant fluxratio is set to 1:2. By changing the current to be injected into eacharea of the packaged LED, the radiant flux irradiated from the packagedLED main body onto the axis can be changed. The CIELAB plot in eachdrawing indicates the a* values and the b* values which are plottedrespectively: when 15 Munsell renotation color samples #01 to #15 aremathematically assumed as the illumination objects and theseillumination objects are illuminated by the packaged LED; and when theseillumination objects are illuminated by a reference light derived fromthe correlated color temperature of the packaged LED. Here the drivepoint names A to E are assigned to the radiant flux of thelight-emitting device in descending order of contribution of the radiantflux of the light emitting area 1. FIG. 76 shows the chromaticity pointsat each of the drive points A to E on the CIE 1976 u′v′ chromaticitydiagram. Table 12 shows the photometric characteristics and colormetriccharacteristics that are expected at each drive point.

TABLE 12 Comparative Example 1     Comparative Example 1       (*1)      (*2)     T_(SSL) (K)       D_(uvSSL)   |Δh_(n)| maximum value  |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 2,880 0.00819 5.78 0.29 −3.33−0.07 −8.02 7.95 133.16 294 92 Point A Drive 2:1 3,360 0.00280 7.02 0.04−1.36 2.81 −3.93 6.73 101.00 294 93 Point B Drive 1.5:1.5 3,749 0.000778.74 0.04 −1.25 3.67 −4.54 8.21 97.77 294 92 Point C Drive 1:2 4,328−0.00025 11.08 0.17 −1.56 4.41 −5.60 10.02 102.18 294 89 Point D Drive0:3 6,814 0.00382 18.10 0.31 −3.20 5.55 −9.51 15.06 116.79 294 81 PointE (*1) Light-emitting elements constituting each light emitting area(*2) Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: blue semiconductor light-emitting element andyellow phosphor

The spectral power distributions in FIG. 71 to FIG. 75, the CIELAB plotsin FIG. 71 to FIG. 75, the CIE 1976 u′v′ chromaticity diagram in FIG. 76and Table 12 clarify the following.

At any of the drive points A to E, one or both of D_(uvSSL) and A_(cg)is/are not in an appropriate range of the first embodiment of the firstto fourth inventions of the present invention. Therefore at any drivepoint, a natural, vivid, highly visible and comfortable appearance ofcolors and appearance of objects, as if the objects are seen outdoors,is not implemented in a variable range as the packaged LED.

Example 5

A 6 mm×9 mm ceramic package, which includes a total of six lightemitting units, as shown in FIG. 50, is prepared. Here a bluesemiconductor light-emitting element, a green phosphor and a redphosphor are mounted and encapsulated in a light emitting area 1-1, alight emitting area 1-2 and a light emitting area 1-3 so as to beequivalent light emitting areas. The semiconductor light-emittingelements in the light emitting area 1-1, the light emitting area 1-2 andthe light emitting area 1-3 are connected in series and connected to oneindependent power supply. On the other hand, a blue semiconductorlight-emitting element, a green phosphor and a red phosphor, which areadjusted differently, are mounted and encapsulated in a light emittingarea 2-1, a light emitting area 2-2 and a light emitting area 2-3, so asto be equivalent light emitting areas. The semiconductor light-emittingelements in the light emitting area 2-1, the light emitting area 2-2 andthe light emitting area 2-3 are connected in series and connected toanother independent power supply. Current can be injected into the lightemitting area 1 and the light emitting area 2 independently from eachother.

Next, if the current value of current injected into each light emittingarea of the packaged LED having the light emitting area 1 and the lightemitting are 2 is appropriately adjusted, five types of spectral powerdistributions shown in FIG. 77 to FIG. 81 irradiated onto the axis ofthe packaged LED, for example, are implemented. FIG. 77 is a case whencurrent is injected only into the light emitting area 1, and the radiantflux ratio of the light emitting area 1 and the light emitting area 2 isset to 3:0, and FIG. 81 is a case when current is injected only into thelight emitting area 2, and the radiant flux ratio of the light emittingarea 1 and the light emitting area 2 is set to 0:3. FIG. 78 is a casewhen the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 2:1, FIG. 79 is a case when the radiant fluxratio is set to 1.5:1.5, and FIG. 80 is a case when the radiant flux isset to 1:2. By changing the current to be injected into each area of thepackaged LED 20, the radiant flux irradiated from the packaged LED mainbody onto the axis can be changed. The CIELAB plot in each drawingindicates the a* values and the b* values which are plottedrespectively: when 15 Munsell renotation color samples #01 to #15 aremathematically assumed as the illumination objects and theseillumination objects are illuminated by the packaged LED; and when theseillumination objects are illuminated by a reference light derived fromthe correlated color template of the packaged LED. Here the drive pointnames A to E are assigned to the radiant flux of the light-emittingdevice in descending order of contribution of the radiant flux of thelight emitting area 1. FIG. 82 shows the chromaticity points at each ofthe drive points A to E on the CIE 1976 u′v′ chromaticity diagram. Table13 shows the photometric characteristics and colormetric characteristicsthat are expected at each drive point.

TABLE 13 Example 5       Example 5       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 2,734 −0.00297 12.23 0.72 1.325.81 −4.18 9.99 4.99 218 85 Point A Drive 2:1 3,542 −0.00625 7.04 0.121.72 5.12 −1.27 6.39 −16.87 230 88 Point B Drive 1.5:1.5 4,146 −0.005475.90 0.52 1.40 4.72 −0.78 5.50 20.03 237 91 Point C Drive 1:2 4,938−0.00292 4.57 0.37 0.84 3.71 −1.15 4.86 94.64 245 94 Point D Drive 0:37,321 0.00690 8.81 0.22 −0.52 4.46 −3.63 8.09 245.15 263 93 Point E (*1)Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: blue semiconductor light-emitting element, greenphosphor and red phosphor

The spectral power distributions in FIG. 77 to FIG. 81, the CIELAB plotsin FIG. 77 to FIG. 81, the CIE 1976 u′v′ chromaticity diagram in FIG. 82and Table 13 clarify the following.

At the drive point A, the drive point C, the drive point D and the drivepoint E, one or both of the D_(uvSSL) and A_(cg) is/are not in anappropriate range of the first embodiment of the first to fourthinventions of the present invention, but in an area near the drive pointB, a natural, vivid, highly visible and comfortable appearance of colorsand appearance of objects, as if the objects are seen outdoors, can beimplemented. For example, in an area near the drive point B, thecorrelated color temperature of the packaged LED can be variable ataround 3542 K, and D_(uvSSL) can also be variable at around −0.00625while implementing the above mentioned appearance of colors. Further,the average saturation difference of 15 Munsell renotation color samplescan also be variable at around 1.72. Thus in the area where a preferableappearance of colors can be implemented, optimum illumination conditionscan easily be selected from the variable range in accordance with theage, gender or the like of the user of the light-emitting device, or inaccordance with the space, purpose or the like of the illumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or the radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 6

A 5 mm diameter resin package in which two light emitting units exist,as shown in FIG. 43, is prepared. In the light emitting area 1, a bluesemiconductor light-emitting element, a green phosphor and a redphosphor are mounted and encapsulated. The blue semiconductorlight-emitting element in the light emitting area 1 constitutes a wiringof the packaged LED, so as to be one independent circuit configuration,and is connected to a power supply. In the light emitting area 2 aswell, a blue semiconductor light-emitting element, a green phosphor anda red phosphor, which are adjusted differently, are mounted andencapsulated. The blue semiconductor light-emitting element in the lightemitting area 2 constitutes a wiring of the packaged LED, so as to beone independent circuit configuration, and is connected to anotherindependent power supply. In this way, current can be injectedindependently into the light emitting area 1 and the light emitting area2 respectively.

Next, if the current value of the current injected into each lightemitting area of the packaged LED 10 including the light emitting area 1and the light emitting area 2 is appropriately adjusted, five types ofspectral power distributions shown in FIG. 83 to FIG. 87 irradiated ontothe axis of the packaged LED, for example, are implemented. FIG. 83 isthe case when the current is injected only into the light emitting area1 and the radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 3:0, and FIG. 87 is a case when current isinjected only into the light emitting area 2, and the radiant flux ratioof the light emitting area 1 and the light emitting area 2 is set to0:3. FIG. 84 is a case when the radiant flux ratio of the light emittingarea 1 and the light emitting area 2 is set to 2:1, FIG. 85 is a casewhen the radiant flux ratio is set to 1.5:1.5, and FIG. 86 is a casewhen the radiant flux ratio if set to 1:2. By changing the current thatis injected into each area of the packaged LED 10, the radiant fluxirradiated from the packaged LED main body onto the axis can be changed.The CIELAB plot in each drawing indicates the a* values and the b*values which are plotted: when 15 Munsell renotation color samples #01to #15 are mathematically assumed as the illumination objects and theseillumination objects are illuminated using this packaged LED; and whenthese illumination objects are illuminated by a reference light derivedfrom the correlated color temperature of the packaged LED. Here thedrive point names A to E are assigned to the radiant flux of thelight-emitting device in descending order of contribution of the radiantflux of the light emitting area 1. FIG. 88 shows the chromaticity pointsat each of the driving points A to E, on the CIE 1976 u′v′ chromaticitydiagram. Table 14 shows the photometric characteristics and colormetriccharacteristics that are expected at each drive point.

TABLE 14 Example 6       Example 6       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0 3,160 −0.01365 3.98 0.08 3.796.05 1.50 4.56 −68.30 217 87 Point A Drive 2:1 3,639 −0.01579 4.70 0.093.66 6.26 1.18 5.08 −87.63 219 86 Point B Drive 1.5:1.5 3,950 −0.016275.04 0.04 3.54 6.53 1.07 5.47 −84.96 221 85 Point C Drive 1:2 4,325−0.01629 5.28 0.02 3.40 6.75 0.99 5.76 −71.80 222 85 Point D Drive 0:35,328 −0.01483 5.83 0.01 3.43 6.78 0.53 6.24 −80.15 225 85 Point E (*1)Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: blue semiconductor light-emitting element, greenphosphor and red phosphor

The spectral power distributions in FIG. 83 to FIG. 87, the CIELAB plotsin FIG. 83 and FIG. 87, the CIE 1976 u′v′ chromaticity diagram in FIG.88 and Table 14 clarify the following.

At the drive point A to the drive point E, and in areas between thesedrive points, a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects, as if the object isviewed outdoors can be implemented. For example, between the drive pointA and the drive point E, the correlated color temperature of thepackaged LED can be variable in a 3160 K to 5328 K range, and D_(uvSSL)can also be variable in the −0.01365 to −0.01629 range. Further, theaverage saturation difference of the fifteen types of Munsell colors canalso be variable in a 3.79 to 3.40 range. Thus in the area where apreferable appearance of colors can be implemented, optimum illuminationconditions can be easily selected from the variable range in accordancewith the age, gender or the like of the user of the light-emittingdevice, or in accordance with the space, purpose or the like of theillumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 7

A light-emitting device, which is a 60 cm×120 cm illumination systemembedded in a ceiling and includes sixteen LED light bulbs (lightemitting units), is prepared as shown in FIG. 57. Here each portionshaded by solid lines is a light emitting area 1, where the same LEDbulb is mounted to form an equivalent light emitting area. Each portionshaded by the dotted lines in FIG. 57 is a light emitting area 2, wherethe same LED bulb is mounted to form an equivalent light emitting area.The LED light bulbs mounted in the plurality of light emitting areas 1are connected in parallel, and connected to one independent powersupply. On the other hand, the LED light bulbs mounted in the pluralityof light emitting areas 2 are connected in parallel and connected toanother independent power supply. The light emitting areas 1 and thelight emitting areas 2 can be driven independently. The LED light bulbconstituting the light emitting area 1 includes a blue semiconductorlight-emitting element, a green phosphor and a red phosphor, and the LEDlight bulb constituting the light emitting area 2 includes a bluesemiconductor light-emitting element, a green phosphor and a redphosphor which are adjusted differently.

If the radiant fluxes of the LED light bulbs constituting the lightemitting area 1 and the light emitting area 2 are appropriately adjustedusing dimming controllers connected to the independent power suppliesrespectively, five types of spectral power distributions shown in FIG.89 to FIG. 93 irradiated onto the central axis of the illuminationsystem, for example, are implemented. FIG. 89 is a case when only theLED light bulbs constituting the light emitting areas 1 are driven andthe radiant flux ratio of the light emitting area 1 and the lightemitting area 2 is set to 5:0, and FIG. 93 is a case when only the LEDlight bulbs constituting the light emitting areas 2 are driven and theradiant flux ratio of the light emitting area 1 and the light emittingarea 2 is set to 0:5. FIG. 90 is a case when the radiant flux ratio ofthe LED light bulbs constituting the light emitting area 1 and the LEDlight emitting area 2 is set to 4:1. FIG. 91 is a case when the radiantflux ratio is set to 2.5:2.5, and FIG. 92 is a case when the radiantflux ratio is set to 1:4. By changing the driving conditions of the LEDlight bulbs constituting each light emitting area, the radiant fluxirradiated onto the central axis of the illumination system can bechanged.

The CIELAB plot in each drawing indicates the a* values and the b*values which are plotted respectively: when 15 Munsell renotation colorsamples #01 to #15 are mathematically assumed as the illuminationobjects and these illumination objects are illuminated using thisillumination system; and when these illumination objects are illuminatedby a reference light derived from the correlated color temperature ofthe light-emitting device of this illumination system. Here the drivepoint names A to E are assigned to the radiant flux of the illuminationsystem (light-emitting device) in descending order of contribution ofthe radiant flux of the LED light bulb constituting the light emittingarea 1. FIG. 94 shows the chromaticity points at each of the drivepoints A to E on the CIE 1976 u′v′ chromaticity diagram. Table 15 showsthe photometric characteristics and colormetric characteristics that areexpected at each drive point.

TABLE 15 Example 7       Example 7       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 5:0 3,327 −0.01546 3.67 0.03 4.067.15 0.79 6.36 −78.32 218 86 Point A Drive 4:1 3,290 −0.01174 2.58 0.113.29 5.74 0.77 4.97 −44.62 224 89 Point B Drive 2.5:2.5 3,243 −0.006601.48 0.14 2.09 3.93 0.72 3.21 −32.27 232 92 Point C Drive 1:4 3,205−0.00190 0.82 0.10 0.84 2.27 −0.02 2.29 1.84 240 95 Point D Drive 0:53,184 0.00100 1.34 0.06 −0.05 1.65 −1.41 3.05 22.44 245 96 Point E (*1)Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1 and spectral power distribution φ_(SSL)2 of lightemitting area 2 (φ_(SSL)1:φ_(SSL)2) (*3) Light emitting area 1: bluesemiconductor light-emitting element, green phosphor and red phosphor;Light emitting area 2: purple semiconductor light-emitting element, bluephosphor, green phosphor and red phosphor

The spectral power distributions in FIG. 89 to FIG. 93, the CIELAB plotsin FIG. 89 to FIG. 93, the CIE 1976 u′v′ chromaticity diagram in FIG. 94and Table 15 clarify the following.

At the drive point D and the drive point E, both D_(uvSSL) and A_(cg)are not in an appropriate range of the first embodiment of the first tofourth inventions of the present invention, but at the drive point A,the drive point B, the drive point C, and areas between and near thesedrive points, a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects, as if the objects areseen outdoors, can be implemented. For example, between the drive pointA and the drive point C, the correlated color temperature as theillumination system can be variable in a 3327 K to 3243 K range, andD_(uvSSL) can also be variable in a −0.01546 to −0.00660 range, whileimplementing the above mentioned appearance of colors. Further, theaverage saturation difference of the 15 Munsell renotation color samplescan also be variable in a 4.06 to 2.09 range. Thus in the area where apreferable appearance of colors can be implemented, optimum illuminationconditions can easily be selected from the variable range in accordancewith the age, gender or the like of the user of the light-emittingdevice, or in accordance with the space, purpose or the like of theillumination.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

Example 8

A ceramic package, in which a 7 mm diameter light emitting unit isdivided into six sub-light emitting units, is prepared. Here a bluesemiconductor light emitting unit, a green phosphor and a red phosphorare mounted and encapsulated in a light emitting area 1-1 and a lightemitting area 1-2, so as to be equivalent light emitting areas. Thesemiconductor light-emitting elements of the light emitting area 1-1 andthe light emitting area 1-2 are connected in series and connected to oneindependent power supply. On the other hand, a blue semiconductorlight-emitting element, a green phosphor and a red phosphor, which areadjusted differently, are mounted in a light emitting area 2-1 and alight emitting area 2-2, so as to be equivalent light emitting areas.The semiconductor light-emitting elements in the light emitting area 2-1and the light emitting area 2-2 are connected in series and connected toanother independent power supply. Further, a blue semiconductorlight-emitting element, a green phosphor and a red phosphor, which areadjusted differently from the light emitting area 1 and the lightemitting area 2, are mounted and encapsulated in the light emitting area3-1 and the light emitting area 3-2, so as to be equivalent lightemitting areas. The semiconductor light-emitting elements of the lightemitting area 3-1 and the light emitting area 3-2 are connected inseries and connected to another independent power supply. Current can beinjected into the light emitting area 1, the light emitting area 2 andthe light emitting area 3 independently from each other.

Next, if the current value of current injected into each light emittingarea of the packaged LED having the light emitting area 1, the lightemitting area 2 and the light emitting area 3 is appropriately adjusted,and four types of spectral power distributions shown in FIG. 95 to FIG.98 irradiated onto the axis of the packaged LED, for example, areimplemented. FIG. 95 is a case when current is injected only into thelight emitting area 1 (adjusted in the same way as FIG. 77), and theradiant flux ratio of the light emitting area 1, the light emitting area2 and the light emitting area 3 is set to 3:0:0. FIG. 96 is a case whencurrent is injected only into the light emitting area 2 (adjusted in thesame way as FIG. 81), and the radiant flux ratio of the light emittingarea 1, the light emitting area 2 and the light emitting area 3 is setto 0:3:0. FIG. 97 is a case when current is injected only into the lightemitting area 3 (adjusted in the same way as FIG. 83), and the radiantflux ratio of the light emitting area 1, the light emitting are 2 andthe light emitting area 3 is set to 0:0:3. And FIG. 98 is a case whencurrent is injected into all of the light emitting area 1, the lightemitting area 2 and the light emitting area 3, and the radiant fluxratio thereof is set to 1:1:1. By changing the current to be injectedinto each area of the packaged LED 25 shown in FIG. 100, the radiantflux irradiated from the packaged LED main body onto the axis can bechanged. The CIELAB plot in each drawing indicates the a* values and theb* values which are plotted respectively: when 15 Munsell renotationcolor samples #01 to #15 are mathematically assumed as the illuminationobjects and these illumination objects are illuminated by the packagedLED; and when these illumination objects are illuminated by a referencelight derived from the correlated color temperature of the packaged LED.Here the drive point names A to D are assigned to the radiant flux ofthe light-emitting device. FIG. 99 shows the chromaticity points at eachof the drive points A to D on the CIE 1976 u′v′ chromaticity diagram.Table 16 shows the photometric characteristics and colormetriccharacteristics that are expected at each drive point.

TABLE 16 Example 8       Example 8       (*1)       (*2)     T_(SSL) (K)      D_(uvSSL)   |Δh_(n)| maximum value   |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}{\Delta C}_{n}}{15}$       ΔC_(max)      ΔC_(min)     |ΔC_(max) − ΔC_(min)|       A_(cg) Luminous efficacy ofradiation (lm/W)       Ra Drive (*3) 3:0:0 2,734 −0.00297 12.23 0.721.32 5.81 −4.18 9.99 4.99 218 85 Point A Drive 0:3:0 7,321 0.00690 8.810.22 −0.52 4.46 −3.63 8.09 245.15 263 93 Point B Drive 0:0:3 3,160−0.01365 3.98 0.08 3.79 6.05 1.50 4.56 −68.30 217 87 Point C Drive 1:1:13,749 −0.00902 5.66 0.16 2.27 5.29 0.34 4.95 −25.48 229 89 Point D (*1)Light-emitting elements constituting each light emitting area (*2)Radiant flux ratio of spectral power distribution φ_(SSL)1 of lightemitting area 1, and spectral power distribution φ_(SSL)2 of lightemitting area 2 and spectral power distribution φ_(SSL)3 of lightemitting area 3 (φ_(SSL)1:φ_(SSL)2:φ_(SSL)3) (*3) Light emitting area 1:blue semiconductor light-emitting element, green phosphor and redphosphor; Light emitting area 2: blue semiconductor light-emittingelement, green phosphor and red phosphor; Light emitting area 3: bluesemiconductor light-emitting element, green phosphor and red phosphor

The spectral power distributions in FIG. 95 to FIG. 98, the CIELAB plotsin FIG. 95 to FIG. 98, the CIE 1976 u′v′ chromaticity diagram in FIG. 99and Table 16 clarify the following.

At the drive point A and the drive point B, both D_(uvSSL) and A_(cg)are not in an appropriate range of the first embodiment of the first tofourth inventions of the present invention, but in an area near andbetween the drive point C and the drive point D, a natural, vivid,highly visible and comfortable appearance of colors and appearance ofobjects, as if the objects are seen outdoors, can be implemented. Forexample, in an area near and between the drive point C and the drivepoint D, the correlated color temperature of the packaged LED can bevariable in a 3160 K to 3749 K range, and D_(uvSSL) can also be variablein a −0.01365 to −0.00902 range, while implementing the above mentionedappearance of colors. Further, the average saturation difference of the15 Munsell renotation color samples can also be variable in a 3.79 to2.27 range. Thus in the area where a preferable appearance of colors canbe implemented, optimum illumination conditions can easily be selectedfrom the variable range in accordance with the age, gender or the likeof the user of the light-emitting device, or in accordance with thespace, purpose or the like of the illumination.

This example is especially preferable since one light-emitting deviceincludes three types of light emitting areas for which colors areadjusted differently, and the variable ranges can be wider compared withthe case when one light-emitting device includes two types of lightemitting areas for which colors are adjusted differently.

In this case, the following drive control is also possible.

First, when at least one of the index A_(cg), correlated colortemperature T_(SSL) (K), and distance D_(uvSSL) from the black-bodyradiation locus, is changed, the luminous flux and/or the radiant fluxemitted from the light-emitting device in the main radiant direction canbe unchangeable. If this control is performed, a difference ofappearance of colors, caused by a change of the shape of the spectralpower distribution, can be easily checked without depending on theluminance of the illumination object, which is preferable.

Second, when the index A_(cg) is decreased in an appropriate range, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.

Third, when D_(uvSSL) is decreased in an appropriate range as well, theluminous flux and/or radiant flux of the light-emitting device can bedecreased, so as to decrease the luminance of the illumination object.In the second and third cases, brightness is normally increased, henceenergy consumption can be suppressed by decreasing luminance, which ispreferable.

Fourth, when the correlated color temperature is increased, the luminousflux and/or radiant flux of the light-emitting device can be increased,so as to increase the luminance of the illumination object. Under ageneral illumination environment, a relatively low luminance environmentis often felt to be comfortable when the color temperature is in a lowrange, and a relatively high luminance environment is often felt to becomfortable when the color temperature is in a high range. Thispsychological effect is known as the Kruithof Effect, and performingcontrol integrating this effect is also possible, and when thecorrelated color temperature is increased, it is preferable to increasethe luminance of the illumination object by increasing the luminous fluxand/or radiant flux of the light-emitting device.

[Examination]

The following invention issues can be derived from the above experimentresults.

In other words, the effect of the first embodiment of the first tofourth inventions of the present invention can be implemented if thelight emitting area allows φ_(SSL)(λ) to satisfy the followingconditions by changing the luminous flux amount and/or radiant fluxamount emitted from the light emitting area, where φ_(SSL)N(λ) (N is 1to M) is a spectral power distribution of a light emitted from eachlight emitting area in a main radiant direction of the light-emittingdevice, and φ_(SSL)(λ) is a spectral power distribution of all thelights emitted from the light-emitting device in the radiant directionand satisfies

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 44} \rbrack \\{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{{N(\lambda)}.}}}}\end{matrix}$

The following conditions can be applied in the same manner to the methodfor designing the light-emitting device according to the firstembodiment of the second invention of the present invention, and themethod for driving the light-emitting device according to the firstembodiment of the third invention of the present invention.

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 45]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 46]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).

In the examples, the light-emitting device includes two types or threetypes of light emitting areas, but a number of types of the lightemitting area is not limited to two or three.

If there are two types of light emitting areas, control of thelight-emitting device is easy, which is preferable.

If there are three types of light emitting areas, the control areabecomes not a line but a plane on the chromaticity coordinates, and theappearance of colors can be adjusted in a wide range, which ispreferable.

If there are four types or more of light emitting areas, not only doesthe control area become a plane on the chromaticity coordinates, asmentioned above, but also the correlated color temperature D_(uvSSL) andthe appearance of colors can be independently controlled, which ispreferable. Furthermore, the appearance of colors can be adjustedwithout changing chromaticity, which is preferable.

If there are too many light emitting areas, on the other hand, controlin the actual light-emitting device becomes complicated, therefore anumber of light emitting areas is preferably ten or less, and even morepreferable is eight or less.

In the light-emitting device which includes a plurality of types oflight emitting areas according to the first embodiment of the firstinvention of the present invention, a following method can be used tochange the luminous flux amount or radiant flux amount of each type ofthe light emitting areas. One method is changing the power to supplyeach light emitting area. For this, a method of changing current ispreferable because it is easy to do. Another method is changing theluminous flux amount and/or radiant flux amount emitted from the lightemitting areas by allowing an optical ND filter to be disposed in eachlight emitting area and exchanging the filter physically, or byelectrically changing the transmittance of the polarizing filter or thelike.

To improve the appearance of colors, it is preferable to satisfy thefollowing Condition 3 and Condition 4.

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light emitted in theradiant direction are respectively denoted by a*_(nref) and b*_(nref)(where n is a natural number from 1 to 15), then each saturationdifference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by the formula(3) satisfies formula (4) below and1.0≦SAT _(av)≦7.0  (4)

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

It is also preferable that all the φ_(SSL)N(λ) (N is 1 to M) of thelight-emitting device satisfies Condition 1 and Condition 2 as shown inExample 1 and Example G. In the case of this mode, a natural, vivid,highly visible and comfortable appearance of colors and appearance ofobjects, as if the objects are seen outdoors, can be implementedregardless the ratio at which the lights emitted from the light emittingareas are supplied. To determine whether φ_(SSL)N(λ) (N is 1 to M)satisfies Conditions 1 and 2, it is assumed that only this φ_(SSL)N(λ)is emitted from the light-emitting device.

On the other hand, light emitted from a single light emitting areaalone, as in the case of Example 2 and Example 5, may be incapable ofimplementing a natural, vivid, highly visible and comfortable appearanceof colors and appearance of objects as if the objects are seen outdoors.Even in such a case, a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects as if the objects areseen outdoors may still be implemented if a combination of lightemitting areas and ratio of the luminous flux and/or radiant flux of thelight emitting areas are adjusted. Needless to say, this type oflight-emitting device still is within the scope of the first embodimentof the first to fourth inventions of the present invention.

As shown in Example 2 and Example 5 for example, one characteristic ofthe first embodiment of the first to fourth inventions of the presentinvention is that “a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects, as if the objects areseen outdoors, can be implemented”, even if “light sources which cannotimplement a natural, vivid, highly visible and comfortable appearance ofcolors and appearance of objects as if the objects are seen outdoors”are combined. Further, as shown in Example 3, Example 4, Example 7 andExample 8, another characteristic is that “a natural, vivid, highlyvisible and comfortable appearance of colors and appearance of objectsas if the objects are seen outdoors” can be implemented, even if “alight source that cannot implement a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects as if theobjects are seen outdoors” as a single unit, and “a light source thatcan implement a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects as if the objects areseen outdoors can be implemented” as a single unit, are combined. Thus,in order to implement a light-emitting device that “can implement anatural, vivid, highly visible and comfortable appearance of colors andappearance of objects as if the objects are seen outdoors”, thefollowing can be used as guidelines to create the light-emitting deviceaccording to the first embodiment of the first invention of the presentinvention, in the case of “a combination including a light source thatcannot implement a natural, vivid, highly visible and comfortableappearance of colors and appearance of objects as if the objects areseen outdoors”, particularly in the case of “a combination of lightsources that cannot implement a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects as if theobjects are seen outdoors”.

(a) Create the light-emitting device by combining light emitting areasof which chromaticity coordinates on various chromaticity diagrams arecompletely different from each other.

(b) Create the light-emitting device by combining a plurality of lightemitting areas of which correlated color temperatures are completelydifferent if the color temperatures can be defined.

(c) Create the light-emitting device by combining a plurality of lightemitting areas of which distance D_(uv) from the black-body radiationlocus are completely different if this distance can be defined.

These aspects will be described in more detail. Requirements toimplement a natural, vivid, highly visible and comfortable appearance ofcolors and appearance of objects as if the objects are seen outdoors areas described above, and in the light-emitting device, it is necessarythat the same parameters on the spectral power distribution of the lightsatisfy predetermined values. Important of these parameters is thedistance D_(uv) from the black-body radiation locus, and a natural,vivid, highly visible and comfortable appearance of colors andappearance of objects, as if the objects are seen outdoors according tothe first embodiment of the first to fourth inventions of the presentinvention, can be implemented by combining light sources that cannotimplement a good appearance of colors, and the reason for this will bedescribed using D_(uv) as an example.

FIG. 56 is the CIE 1976 u′v′ chromaticity diagram, on which the two-dotchain line indicates a range of D_(uv) that satisfies Condition 1according to the first embodiment of the first to fourth inventions ofthe present invention.

The light source at A and the light source at E in FIG. 56, which arelight sources outside this range, cannot implement a good appearance ofcolors alone. However if the light source at A and the light source at Ein FIG. 56 are combined and the radiant flux ratio or luminous fluxratio thereof is changed, the combined light source can be moved on theline connecting point A and point E. Then the optimum range of D_(uv)according to the first embodiment of the first to fourth inventions ofthe present invention draws not a line but an arc, hence point B orpoint C, when lights from the light sources are combined at apredetermined ratio, can exist in a range where a good appearance ofcolors can be implemented.

A number of combinations that implement this combination is infinite,and in FIG. 56, the light source A of which correlated color temperatureis low (2700 K) and light source E of which correlated color temperatureis high (5506 K) are combined. The chromaticity diagram in FIG. 82 issimilar to this. It is also possible to combine a light source, of whichvalue of D_(uv) is extremely low and is outside the range of D_(uv) toimplement a good appearance of colors, and a light source, of whichvalue of D_(uv) is extremely high and is outside the range of D_(uv) toimplement a good appearance of colors.

Therefore in (a), (b) and (c), it is preferable that the range of D_(uv)(−0.0350 or more and −0.004 or less), disclosed in the first embodimentof the first to fourth inventions of the present invention and the rangeof chromaticity that can be implemented by combining the light emittingareas, overlap at least partially, and it is more preferable that theseranges overlap on a plane of the chromaticity diagram by using three ormore light emitting areas.

Concerning Condition (b), the correlated color temperature differencebetween two light emitting areas, of which correlated color temperaturesare most different among the plurality of light emitting areasconstituting the light-emitting device, is favorably 2000 K or more,more favorably 2500 K or more, extremely favorably 3000 K or more,dramatically favorably 3500 K or more, and most favorably 4000 K ormore. Concerning Condition (c), the absolute value of the D_(uv)difference between two light emitting areas, of which correlated colortemperatures are most different among the plurality of light emittingareas constituting the light-emitting device, is favorably 0.005 ormore, more favorably 0.010 or more, extremely favorably 0.015 or more,and dramatically favorably 0.020 or more.

In order to implement the light-emitting device that “can implement anatural, vivid, highly visible and comfortable appearance of colors andappearance of objects as if the objects are seen outdoors”, thefollowing can also be used as guidelines to create the light-emittingdevice according to the first embodiment of the first invention of thepresent invention, in the case of “a combination including a lightsource that cannot implement a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects as if theobjects are seen outdoors”, particularly in the case of “a combinationof light sources that cannot implement a natural, vivid, highly visibleand comfortable appearance of colors and appearance of objects as if theobjects are seen outdoors”.

(d) Create the light-emitting device by combining a plurality of lightemitting areas of which respective A_(cg) is completely different fromeach other in the appearance of colors.

(e) Create the light-emitting device by combining a plurality of lightemitting areas of which each saturation difference ΔC_(n) is completelydifferent from each other in the appearance of colors.

(f) Create the light-emitting device by combining a plurality of lightemitting areas of which average SAT_(av) of the saturation difference iscompletely different from each other in the appearance of colors.

In (d), (e) and (f) as well, it is preferable that the respective rangedisclosed in the first embodiment of the first to fourth inventions ofthe present invention and the range of each parameter that can beimplemented by the combination of the light emitting area overlap atleast partially, and it is more preferable that these ranges overlap ona plane of the chromaticity diagram by using three or more lightemitting areas.

If four or more light emitting areas are used, all the items of (a) to(f) can be quite easily adjusted to be in the range disclosed by thefirst embodiment of the first to fourth inventions of the presentinvention, even if all the light emitting areas are “light sources thatcannot implement a natural, vivid, highly visible and comfortableappearance of color and appearance of objects as if the objects are seenoutdoors”, which is preferable.

In the first embodiment of the first to fourth inventions of the presentinvention, it is preferable that at least one of the light emittingareas is a light emitting area having wiring that can be electricallydriven independently from the other light emitting areas, and it is morepreferable that all the light emitting areas have wiring that can beelectrically driven independently from the other light emitting areas.It is also preferable to drive the light-emitting device in this way. Inthis mode, power to be supplied to each light emitting area can beeasily controlled, and the appearance of colors suitable to the taste ofthe user can be implemented.

In the first embodiment of the first to fourth inventions of the presentinvention, one light emitting area may be driven so as to beelectrically subordinate to another light emitting area. For example,when current is injected into two light emitting areas, one lightemitting area may be electrically subordinate to the other, such thatwhen current to be injected into one light emitting area is increased,current to be injected into the other light emitting area is decreased.This circuit is easily implemented by a configuration using a variableresistor or the like, for example, and does not require a plurality ofpower supplies, which is preferable.

In the light-emitting device, it is preferable that at least oneselected from the group consisting of: the index A_(cg) given by theExpression (1) or (2), the correlated color temperature T_(SSL)(K) andthe distance D_(uvSSL) from the black-body radiation locus, can bechanged, and it is also preferable that the luminous flux and/or radiantflux emitted from the light-emitting device in the main radiantdirection can be independently controlled when at least one selectedfrom the group consisting of: the index A_(cg) given by the Expression(1) or (2), the correlated color temperature T_(SSL)(K) and the distanceD_(uvSSL) from the black-body radiation locus is changed. It ispreferable to drive the light-emitting device in this way. In this mode,parameters to implement appearance of colors are variable, and anappearance of colors suitable to the taste of the user can be easilyimplemented.

It is preferable that the maximum distance L between two arbitrarypoints on a virtual outer periphery enveloping the entire light emittingareas closest to each other is 0.4 mm or more and 200 mm or less. Inthis mode, the color separation of the lights emitted from a pluralityof light emitting areas is not visually recognized clearly, and thestrange feeling of seeing an image generated by the light-emittingdevice can be reduced. Further, the spatial additive color mixing in theillumination light functions sufficiently, and when this light isirradiated onto the illumination object, color unevenness in theilluminated area can be reduced, which is preferable.

The maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light emitting areas will be describedwith reference to drawings.

FIG. 50 shows the packaged LED 20 used for Example 2, where the lightemitting areas closest to the light emitting area 22 is the lightemitting areas 11, 12 and 13. Out of these light emitting areas, thevirtual outer periphery 7 enveloping the light emitting area 12 is thelargest virtual outer periphery, and the arbitrary two points 71 on thisouter periphery is the maximum distance L. In other words, the maximumdistance L is the distance 72 between these two points, which ispreferably 0.4 mm or more and 200 mm or less.

This is the same for the illumination system 30 used for Example 3 inFIG. 57 and the pair of packaged LEDs 40 used for Example 4 in FIG. 64.

The maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light emitting areas closest to eachother is favorably 0.4 mm or more, more favorably 2 mm or more,extremely favorably 5 mm or more, and dramatically favorably 10 mm ormore. This is because the higher radiant flux (and/or higher luminousflux) can be emitted as the virtual outer periphery enveloping one lightemitting area is larger. The maximum distance L between two arbitrarypoints on the virtual outer periphery enveloping the entire lightemitting areas closest to each other is favorably 200 mm or less, morefavorably 150 mm or less, extremely favorably 100 mm or less, anddramatically favorably 50 mm or less. This is critical in terms ofsuppressing the generation of spatial color unevenness in theilluminated area.

In a driving method according to the first embodiment of the thirdinvention of the present invention, when at least one selected from thegroup consisting of: the index A_(cg), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus, is changed, the luminous flux and/or radiant flux emitted fromthe light-emitting device in the main radiant direction may be made tobe unchangeable. If this control is performed, the difference ofappearance of colors caused by the change of the shape of the spectralpower distribution can be easily checked without depending on theluminance of the illumination object, which is preferable.

In the method for driving the light-emitting device, it is preferablethat when the index A_(cg) given by the Expression (1) or (2) isdecreased within an appropriate range, the luminous flux and/or radiantflux emitted from the light-emitting device in the main radiantdirection is decreased, or it is preferable that when the correlatedcolor temperature T_(SSL)(K) is increased, the luminous flux and/orradiant flux emitted from the light-emitting device in the main radiantdirection is increased, or it is preferable that when the distanceD_(uvSSL) from the black-body radiation locus is decreased within anappropriate range, the luminous flux and/or radiant flux emitted fromthe light-emitting device in the main radiant direction is decreased.This also means that it is preferable that when the index A_(cg) givenby the Expression (1) or (2) is increased within an appropriate range,the luminous flux and/or radiant flux emitted from the light-emittingdevice in the main radiant direction is increased, or it is preferablethat when the correlated color temperature T_(SSL)(K) is decreased, theluminous flux and/or radiant flux emitted from the light-emitting devicein the main radiant direction is decreased, or it is preferable thatwhen the distance D_(uvSSL) from the black-body radiation locus isincreased within an appropriate range, the luminous flux and/or radiantflux emitted from the light-emitting device in the main radiantdirection is increased.

When the index A_(cg) given by the Expression (1) or (2) is decreased, anatural, vivid, highly visible and comfortable appearance of colors andappearance of objects as if the objects are seen outdoors can beimplemented. According to various visual experiments, if the indexA_(cg) is decreased like this, a sense of brightness improves, henceeven if the luminous flux and/or radiant flux or luminance to bemeasured is decreased, a good appearance of colors can still bemaintained in the illumination object, and therefore energy consumptionof the light-emitting device can be conserved, which is preferable. Inthe same manner, when the index A_(cg) is increased within anappropriate range, it is preferable to maintain a good appearance ofcolors in the illumination object by increasing the luminous flux and/orradiant flux or the luminance to be measured.

If it is driven such that the luminous flux and/or radiant flux isincreased when the correlated color temperature T_(SSL)(K) is increased,comfortable illumination can be implemented by the Kruithof Effect. Whenthe color temperature is decreased, on the other hand, it may becontrolled to decrease the luminous flux and/or radiant flux of thelight-emitting device so as to decrease the luminance of theillumination object. These are control techniques applying the KruithofEffect, and are preferable.

When the distance D_(uvSSL) from the black-body radiation locus isdecreased within an appropriate range, a natural, vivid, highly visibleand comfortable appearance of colors and appearance of objects as if theobjects are seen outdoors can be implemented. According to variousvisual experiments, if the distance D_(uvSSL) from the black-bodyradiation locus is decreased within an appropriate range like this, asense of brightness improves, hence even if the luminous flux and/orradiant flux or luminance to be measured is decreased, a good appearanceof colors can still be maintained in the illumination object, andtherefore energy consumption of the light-emitting device can beconserved, which is preferable. In the same manner, when the distanceD_(uvSSL) from the black-body radiation locus is increased within anappropriate range, it is preferable to maintain a good appearance ofcolors in the illumination object by increasing the luminous flux and/orradiant flux or the luminance to be measured.

In the first embodiment of the first to fourth inventions of the presentinvention, it is also possible to perform the opposite of the abovementioned control, and needless to say, that the control method can beappropriately selected depending on the illumination object, theillumination environment, the purpose or the like.

On the other hand, the following invention issues can be derived fromthe experiment results.

In other words, the effect of the first embodiment of the first tofourth inventions of the present invention can be implemented by usingan illumination method comprising:

illuminated objects preparation step of preparing illuminated objects;and

an illumination step of illuminating the objects by light emitted from alight-emitting devices which includes M number of light-emitting areas(M is 2 or greater natural number), and has a semiconductorlight-emitting element as a light-emitting element

in at least one of the light-emitting areas, in the illumination step,when light emitted from the light-emitting devices illuminate theobjects, the objects are illuminated so that the light measured at aposition of the objects satisfies <1>, <2> and <3> below:

<1> a distance D_(uvSSL) from a black-body radiation locus as defined byANSI C78.377 of the light measured at the position of the objectssatisfies −0.0350≦D_(uvSSL)≦−0.0040;

<2> if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light measured at theposition of the objects are respectively denoted by a*_(nSSL) andb*_(nSSL) (where n is a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light measured at theposition of the objects are respectively denoted by a*_(nref) andb*_(nref) (where n is a natural number from 1 to 15), then eachsaturation difference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by the formula(3) satisfies formula (4) below and1.0≦SAT _(av)≦7.0,

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference ΔC_(max)−ΔC_(min) between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

<3> if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light measured at the position of the objects are denoted byθ_(nSSL) (degrees) (where n is a natural number from 1 to 15), and

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light measured at the position of theobjects are denoted by θ_(nref) (degrees) (where n is a natural numberfrom 1 to 15), then an absolute value of each difference in hue angles|Δh_(n)| satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

here Δh_(n)=θ_(nSSL)−θ_(nref).

It is preferable that when φ_(SSL)N(λ) (N is 1 to M) is a spectral powerdistribution of a light which was emitted from each light-emittingelement and reached the position of the object, and φ_(SSL)(λ) is aspectral power distribution of the light measured at the position of theobject is given by

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 47} \rbrack \\{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{{N(\lambda)}.}}}}\end{matrix}$all of φ_(SSL)N(λ) can satisfy the above mentioned <1>, <2> and <3>.

In the illumination method, it is preferable that at least one lightemitting area of the M number of light emitting areas is electricallydriven independently from the other light emitting areas for performingthe illumination, and it is more preferable that all of the lightemitting areas of the M number of light emitting areas are electricallydriven independently from the other light emitting areas.

In the illumination method, it is preferable that at least one of: theindex SAT_(av), the correlated color temperature T_(SSL)(K), and thedistance D_(uvSSL) from the black-body radiation locus is changed, or itis preferable that when at least one of the indexes is changed, theluminance in the object is independently controlled, or it is preferablethat when at least one of the indexes is changed, the luminance in theobject is made to be unchangeable.

Making the luminance unchangeable means that the luminance is notsubstantially changed, and the change of the luminance is favorably ±20%or less, more favorably ±15% or less, even more favorably ±10% or less,particularly favorably ±5% or less, and most favorably ±3% or less. Ifthis method is used, the difference of appearance of colors caused bythe change of the shape of the spectral power distribution can be easilychecked without depending on the luminance of the illumination object,and optimum spectral power distribution depending on the illuminationenvironment, the object, the purpose or the like can be easily detected,which is preferable.

In the illumination method, it is preferable that when the indexSAT_(av) is increased, the luminance in the object is decreased. If theindex is increased, a more vivid appearance can be implemented, and asense of brightness normally increased in this situation, hence theluminance can be decreased, whereby energy consumption can be conserved.This also means that it is preferable that when the index SAT_(av) isdecreased, the luminance in the object is increased.

In the illumination method, it is preferable that when the correlatedcolor temperature T_(SSL)(K) is increased, the luminance in the objectis increased. If it is driven such that the luminance is increased whenthe correlated color temperature T_(SSL)(K) is increased, a comfortableillumination can be implemented by the Kruithof Effect. When the colortemperature is decreased, on the other hand, it may be controlled todecrease the luminance of the illumination object. These are controltechniques applying the Kruithof effect, and are preferable.

In the illumination method, it is preferable that when the distanceD_(uvSSL) from the black-body radiation locus is decreased, theluminance in the object is decreased. According to various visualexperiments, if the distance D_(uvSSL) from the black-body radiationlocus is decreased, a sense of brightness improves, hence even if theluminance is decreased, a good appearance of colors can still bemaintained in the illumination object, and therefore energy consumptionof the light-emitting device can be conserved, which is preferable. Inthe same manner, when the distance D_(uvSSL) from the black-bodyradiation locus is increased, it is preferable to maintain a goodappearance of colors in the illumination object by increasing theluminance.

In the illumination method, it is preferable that when L is a maximumdistance between two arbitrary points on a virtual outer peripheryenveloping the entire light emitting areas closest to each other, and His a distance between the light-emitting device and the illuminationobject, the distance His set so as to satisfy 5×L≦H≦500×L.

In this case, the base point of the light-emitting device to measure thedistance is the irradiation port.

If this illumination method is used, color separation of lights from thelight sources is not visually recognized clearly when the light-emittingdevice is observed from the position of the illumination object, andspatial color unevenness is hardly generated in the illumination object,which is preferable.

In the maximum distance L between two arbitrary points on a virtualouter periphery enveloping the entire light emitting areas closest toeach other, and the distance H between the light-emitting device and theillumination object, H is favorably 5×L or more, more favorably 10×L ormore, extremely favorably 15×L or more, and dramatically favorably 20×Lor more. Because as H is greater within an appropriate range, that is,as H is more distant from the maximum distance L between two arbitrarypoints on a virtual outer periphery enveloping different light emittingareas, the colors of the lights emitted from different light emittingareas are more thoroughly mixed spatially, which is preferable. On theother hand, H is favorably 500×L or less, more favorably 250×L or less,extremely favorably 100×L or less, and dramatically favorably 50×L orless. Because if H is more distant than necessary, sufficient luminancecannot be assured for the illumination object, and maintaining thedistance of H and L within this range is important to implement a goodluminance environment with driving power in an appropriate range.

Second Embodiment of First, Second, Fourth and Fifth Inventions of thePresent Invention Example 9

First an optical filter having spectral transmission characteristicsshown in FIG. 101 is prepared. Then a packaged LED having a purple LED,an SBCA phosphor, a β-SiAlON phosphor and a CASON phosphor, as alight-emitting element, is prepared, and six of the packaged LEDs aremounted on an LED board, whereby an LED module is fabricated. The dottedline in FIG. 102 indicates the spectral power distribution in this case,normalized by the maximum spectral radiant flux irradiated from the LEDmodule onto the axis. FIG. 103 shows this spectral power distribution,and the CIELAB plot on which the a* values and the b* values areindicated: when the 15 Munsell renotation color samples from #01 to #15are mathematically assumed as illumination objects and are illuminatedby this LED module; and when these illumination objects are illuminatedby the reference light derived from the correlated color temperature ofthe LED module. Further, the photometric characteristics and thecolormetric characteristics in this case are shown in Reference Example1 in Table 17. Here the light emitted from the LED module of theReference Example 1 onto the axis implements a good appearance ofcolors, as each value clearly indicates.

Next, an LED lighting fixture of Example 9 is fabricated using the LEDmodule. Here an optical filter having the spectral transmissioncharacteristics shown in FIG. 101 is mounted in the light emittingdirection. The solid line in FIG. 102 is a spectral power distributionof the LED lighting fixture of Example 9, normalized by the maximumspectral radiant flux of the light irradiated from the LED module ontothe axis. In the spectral power distribution of the LED lighting fixtureof Example 9, convex/concave portions are added because of thecharacteristics of the optical filter. FIG. 103 shows this spectralpower distribution, and the CIELAB plot on which the a* values and theb* values are indicated: when 15 Munsell renotation color samples from#01 to #15 are mathematically assumed as illumination objects and areilluminated by the LED lighting fixture of Example 9; and when theseobjects are illuminated by the reference light derived from thecorrelated color temperature of the LED lighting fixture. Further, thephotometric characteristics and the colormetric characteristics in thiscase are shown in Example 9 in FIG. 17.

D_(uv) (φ_(SSL)) of the lighting fixture of Example 9 is −0.02063, whichis 0.00047 higher than −0.02110 of D_(uv) (Φ_(elm)) of the LED module ofReference Example 1. A_(cg) (φ_(SSL)) of the lighting fixture of Example9 is −267.09, which is 20.39 lower than −246.70 of A_(cg) (Φ_(elm)) ofthe LED module of Reference Example 1. SAT_(av) (φ_(SSL)) of thelighting fixture of Example 9 is 5.06, which is 0.92 higher than 4.14 ofSAT_(av) (Φ_(elm)) of the LED module of Reference Example 1, and a moreclear and better appearance of colors is implemented when observed witha same luminance.

Example 10

First an optical filter having spectral transmission characteristicsshown in FIG. 104 is prepared. Then a semiconductor light-emittingelement having four types of central wavelengths is prepared as alight-emitting element, and four of the semiconductor light-emittingelements are mounted on one package, whereby a packaged LED isfabricated. Then twelve of the packaged LEDs are mounted on an LEDboard, whereby an LED module is fabricated. The dotted line in FIG. 105indicates the spectral power distribution in this case, normalized bythe maximum spectral radiant flux of the light irradiated from this LEDmodule onto the axis. FIG. 106 shows this spectral power distribution,and the CIELAB plot on which the a* values and the b* values areindicated: when the 15 Munsell renotation color samples from #01 to #15are mathematically assumed as illumination objects and are illuminatedby this LED module; and when these illumination objects are illuminatedby the reference light derived from the correlated color temperature ofthe LED module. Further, the photometric characteristics and thecolormetric characteristics in this case are shown in the ReferenceComparative Example 1 in FIG. 17. Here the light emitted from the lightemitted from the LED module according to Reference Comparative Example 1onto the axis does not implement a good appearance of colors, as eachvalue clearly indicates.

Next, an LED lighting fixture of Example 10 is fabricated using the LEDmodule. Here an optical filter shown in FIG. 104 is mounted in the lightemitting direction. The solid line in FIG. 105 is a spectral powerdistribution of the LED lighting fixture according to Example 10,normalized by the maximum spectral radiant flux of the light irradiatedfrom the LED module onto the axis. In the spectral power distribution ofthe LED lighting fixture of Example 10, the relative intensity of theradiant flux changes due to the emission of the LED, and concave/convexportions are added because of the characteristics of the optical filter.FIG. 106 shows this spectral power distribution, and the CIELAB plot onwhich the a* values and the b* values are indicated: when 15 Munsellrenotation color samples from #01 to #15 are mathematically assumed asillumination objects and are illuminated by the LED lighting fixture ofExample 10; and when these objects are illuminated by the referencelight derived from the correlated color temperature of the LED lightingfixture. Further, the photometric characteristics and the colormetriccharacteristics in this case are shown in Example 10 in Table 17.

D_(uv) (φ_(SSL)) of the lighting fixture of Example 10 is −0.00424,which is 0.00453 lower than 0.00029 of D_(uv) (Φ_(elm)) of the LEDmodule of Reference Comparative Example 1. A_(cg) (φ_(SSL)) of thelighting fixture of Example 10 is −81.41, which is 74.66 lower than−6.75 of A_(cg) (Φ_(elm)) of the LED module of Reference ComparativeExample 1. SAT_(av) (φ_(SSL)) of the lighting fixture of Example 10 is5.28, which is 3.69 higher than 1.59 of SAT_(av) of the LED module ofReference Comparative Example 1.

As a result, even if a lighting fixture uses a semiconductorlight-emitting element, a packaged LED and an LED module which cannotimplement a good appearance of colors, an LED lighting fixture that canimplement a good appearance of colors can be fabricated by the opticalcharacteristics of a control element.

Comparative Example 2

An LED module of Reference Comparative Example 2 and an LED lightingfixture of Comparative Example 2 are fabricated in the same manner asExample 9, except that a packaged LED having a blue LED, a greenphosphor and a red phosphor is prepared as the light-emitting element.

The dotted line in FIG. 107 indicates the spectral power distribution inthis case, normalized by the maximum spectral radiant flux of the lightirradiated from the LED module onto the axis. FIG. 108 shows thisspectral power distribution, and the CIELAB plot on which the a* valuesand the b* values are indicated: when the 15 Munsell renotation colorsamples from #01 to #15 are mathematically assumed as illuminationobjects and are illuminated by this LED module; and when theseillumination objects are illuminated by the reference light derived fromthe correlated color temperature of the LED module. Further, thephotometric characteristics and the colormetric characteristics in thiscase are shown in Reference Comparative Example 2 in Table 17. Here thelight emitted from the LED module of Reference Comparative Example 2onto the axis does not implement a good appearance of colors, as eachvalue clearly indicates.

On the other hand, the characteristics of the LED lighting fixture ofComparative Example 2 fabricated by mounting the optical filter shown inFIG. 98, which is the same as Example 9, are as follows. The solid linein FIG. 107 is a spectral power distribution of the LED lighting fixtureof Comparative Example 2, normalized by the maximum spectral radiantflux of the light irradiated from the LED module onto the axis. In thespectral power distribution of the LED lighting fixture of ComparativeExample 2, convex/concave portions are added because of thecharacteristics of the optical filter. FIG. 108 shows this spectralpower distribution, and the CIELAB plot on which the a* values and theb* values are indicated: when 15 Munsell renotation color samples from#01 to #15 are mathematically assumed as illumination objects and areilluminated by the LED lighting fixture of Comparative Example 2; andwhen these objects are illuminated by the reference light derived fromthe correlated color temperature of the LED lighting fixture. Further,the photometric characteristics and colormetric characteristics in thiscase are shown in Comparative Example 2 in Table 17.

D_(uv) (φ_(SSL)) of the lighting fixture of Comparative Example 2 is0.00716, which is 0.00103 lower than 0.00819 of D_(uv) (Φ_(elm)) of theLED module of Reference Comparative Example 2. A_(cg) (φ_(SSL)) of thelighting fixture of Comparative Example 2 is 120.86, which is 35.29lower than 156.15 of A_(cg) (Φ_(elm)) of the LED module of ReferenceComparative Example 2. SAT_(av) (φ_(SSL)) of the lighting fixture ofComparative Example 2 is −2.44, which is 0.89 higher than −3.33 ofSAT_(av) (Φ_(elm)) of the LED module of Reference Comparative Example 2.

As a result, even if a control element that can implement a goodappearance of colors when combined with a specific light-emittingelement, a good appearance of colors may be implemented when thiscontrol element is combined with a lighting fixture using a differentsemiconductor light-emitting element, packaged LED and LED module.

TABLE 17 Light- emitting element Control element CCT (K) D_(uv) |Δh_(n)|maximum value |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}\;{\Delta\; C_{n}}}{15}$ ΔC_(max)ΔC_(min) |ΔC_(max) − ΔC_(min)| A_(cg) Luminous efficacy of radiation(lm/W) Ra Reference Purple LED NO 3,292 −0.02110 7.07059 0.58200 4.149.91 −1.20 11.12 −246.70 211 88 Example 1 SBCA β-SiAlON CASON Example 9Purple LED YES 3,164 −0.02063 8.05371 0.01491 5.06 9.66 −0.36 10.02−267.09 199 82 SBCA β-SiAlON CASON Reference Four types NO 4,095 0.000295.68812 0.09747 1.59 6.08 −1.07 7.15 −6.75 334 93 Compar- of semi- ativeconductor Example 1 light- emitting elements Example 10 Four types YES4,421 −0.00424 8.01986 0.23345 5.28 13.58 −0.77 14.35 −81.41 302 69 ofsemi- conductor light- emitting elements Reference Blue LED NO 2,8800.00819 5.78057 0.29252 −3.33 −0.07 −8.02 7.95 156.15 295 92 Compar-Green ative phosphor Example 2 Red phosphor Compar- Blue LED YES 2,8080.00716 5.75545 0.16895 −2.44 1.06 −8.51 9.56 120.86 272 96 ative GreenExample 2 phosphor Red phosphor

Example 11

First an optical filter having spectral transmission characteristicsshown in FIG. 101 is prepared. Then a packaged LED having a blue LED, aCSO phosphor and a CASN phosphor is prepared as a light-emittingelement, and eighteen of the packaged LEDs are mounted on an LED board,whereby an LED module is fabricated.

The dotted line in FIG. 109 indicates the spectral power distribution inthis case, normalized by the maximum spectral radiant flux irradiatedfrom the LED module onto the axis. FIG. 110 shows this spectral powerdistribution, and the CIELAB plot on which the a* values and the b*values are indicated: when the Munsell renotation color samples from #01to #15 are mathematically assumed as illumination objects and areilluminated by this LED module; and when these illumination objects areilluminated by the reference light derived from the correlated colortemperature of the LED module. Further, the photometric characteristicsand the colormetric characteristics in this case are shown in ReferenceExample 2 in Table 18. Here the light emitted from the LED module ofReference Example 2 onto the axis implements a good appearance ofcolors, as each value clearly indicates.

TABLE 18 Light- emitting element Control element CCT (K) D_(uv) |Δh_(n)|maximum value |Δh_(n)| minimum value$\frac{\sum\limits_{n - 1}^{15}\;{\Delta\; C_{n}}}{15}$ ΔC_(max)ΔC_(min) |ΔC_(max) − ΔC_(min)| A_(cg) Luminous efficacy of radiation(lm/W) Ra Reference Blue LED NO 3,606 −0.01115 3.85010 0.16256 3.08 5.640.52 5.12 −24.30 228 89 Example 2 CSO CASN Example 11 Blue LED YES 3,470−0.01160 5.77707 0.07539 4.13 8.10 1.29 6.82 −120.97 210 82 CSO CASNReference Blue LED NO 3,661 −0.00129 5.35826 0.03805 0.51 3.18 −1.915.09 141.23 263 96 Compar- LuAG CASN ative Example 3 Example 12 Blue LEDYES 3,762 −0.00593 6.67286 0.43365 3.45 8.67 0.46 8.20 −19.95 234 81LuAG CASN

Next, an LED lighting fixture of Example 11 is fabricated using the LEDmodule. Here an optical filter having the spectral transmissioncharacteristics shown in FIG. 101 is mounted in the light emittingdirection. The solid line in FIG. 109 is a spectral power distributionof the LED lighting fixture of Example 11, normalized by the maximumspectral radiant flux of the light irradiated from the LED module ontothe axis. In the spectral power distribution of the LED lighting fixtureof Example 11, convex/concave portions are added because of thecharacteristics of the optical filter. FIG. 110 shows this spectralpower distribution, and the CIELAB plot on which the a* values and theb* values are indicated: when 15 Munsell renotation color samples from#01 to #15 are mathematically assumed as illumination objects and areilluminated by the LED lighting fixture of Example 9; and when theseobjects are illuminated by the reference light derived from thecorrelated color temperature of the LED lighting fixture. Further, thephotometric characteristics and the colormetric characteristics in thiscase are shown in Example 11 in Table 18.

D_(uv) (φ_(SSL)) of the lighting fixture of Example 11 is −0.01160,which is 0.00045 higher than −0.01115 of D_(uv) (Φ_(elm)) of the LEDmodule of Reference Example 2. A_(cg) (φ_(SSL)) of the lighting fixtureof Example 11 is −120.97, which is 96.67 lower than −24.30 of A_(cg)(Φ_(elm)) of the LED module of Reference Example 2. SAT_(av) (φ_(SSL))of the lighting fixture of Example 9 is 4.13, which is 1.05 higher than3.08 of SAT_(av) (Φ_(elm)) of the LED module of Reference Example 1, anda more clear and better appearance of colors is implemented whenobserved with a same luminance.

Example 12

First an optical filter having spectral transmission characteristicsshown in FIG. 104 is prepared. Then a packaged LED having a blue LED, anLuAG phosphor and a CASN phosphor is fabricated as a light-emittingelement. Then eighteen of the packaged LEDs are mounted on an LED board,whereby an LED module is fabricated. The dotted line in FIG. 111indicates the spectral power distribution in this case, normalized bythe maximum spectral radiant flux irradiated from the LED module ontothe axis. FIG. 112 shows this spectral power distribution, and theCIELAB plot on which the a* values and the b* values are indicated: whenthe 15 Munsell renotation color samples from #01 to #15 aremathematically assumed as illumination objects and are illuminated bythis LED module; and when these illumination objects are illuminated bythe reference light derived from the correlated color temperature of theLED module. Further, the photometric characteristics and the colormetriccharacteristics in this case are shown in Reference Comparative Example3 in Table 18. Here the light emitted from the LED module of ReferenceComparative Example 3 onto the axis does not implement a good appearanceof colors, as each value clearly indicates.

Next, an LED lighting fixture of Example 12 is fabricated using the LEDmodule. Here an optical filter shown in FIG. 104 is mounted in the lightemitting direction. The solid line in FIG. 111 is a spectral powerdistribution of the LED lighting fixture according to Example 12,normalized by the maximum spectral radiant flux of the light irradiatedfrom the LED module onto the axis. In the spectral power distribution ofthe LED lighting fixture of Example 12, the relative intensity of theradiant flux changes due to the emission of the LED, and concave/convexportions are added because of the characteristics of the optical filter.FIG. 112 shows this spectral power distribution, and the CIELAB plot onwhich the a* values and the b* values are indicated: when 15 Munsellrenotation color samples from #01 to #15 are mathematically assumed asillumination objects and are illuminated by the LED lighting fixture ofExample 10; and when these objects are illuminated by the referencelight derived from the correlated color temperature of the LED lightingfixture. Further, the photometric characteristics and the colormetriccharacteristics in this case are shown in Example 12 in Table 18.

D_(uv) (φ_(SSL)) of the lighting fixture of Example 12 is −0.00593,which is 0.00464 lower than −0.00129 of D_(uv) (Φ_(elm)) of the LEDmodule of Reference Comparative Example 3. A_(cg) (φ_(SSL)) of thelighting fixture of Example 12 is −19.95, which is 161.18 lower than141.23 of A_(cg) (Φ_(elm)) of the LED module of Reference ComparativeExample 3. SAT_(av) (φ_(SSL)) of this lighting fixture is 3.45, which is2.94 higher than 0.51 of SAT_(av) (Φ_(elm)) of the LED module ofReference Comparative Example 3.

As a result, even if a lighting fixture uses a semiconductorlight-emitting element, a packaged LED and an LED module which cannotimplement a good appearance of colors, an LED lighting fixture that canimplement a good appearance of colors can be fabricated by the opticalcharacteristics of the control element.

(Discussion)

The following invention issues can be derived from the above mentionedexperiment results.

As a result of Reference Comparative Example 1 and Example 10, or theresult of Reference Comparative Example 3 and Example 12 show, thelight-emitting devices of Example 10 and Example 12, which can implementa good appearance of colors, can be implemented respectively bydisposing an appropriate control element in the light-emitting device ofReference Comparative Example 1 and Reference Comparative Example 3(regarded as a light-emitting element in the second embodiment of thefirst invention of the present invention), which cannot implement a goodappearance of colors.

In other words, in a light-emitting device having a light-emittingelement, which includes a semiconductor light-emitting element, and acontrol element, when λ(nm) is a wavelength, Φ_(elm)(λ) is a spectralpower distribution of a light which is emitted from the light-emittingelement in a main radiant direction, φ_(SSL)(λ) is a spectral powerdistribution of a light which is emitted from the light-emitting elementin the main radiant direction, and Φ_(elm)(λ) does not satisfy at leastone of the following Condition 1 and Condition 2, and φ_(SSL)(λ)satisfies both the following Condition 1 and Condition 2, thelight-emitting device (light-emitting element) which does not implementa good appearance of colors becomes a light-emitting device which canimplement a good appearance of colors by the control element.

Particularly, if a specific control element is disposed in an LEDlighting fixture which is already on the market and has not yetimplemented a good appearance of colors, this LED lighting device canbecome a light-emitting device which can implement a good appearance ofcolors according to this embodiment.

Condition 1 and Condition 2 according to this embodiment are conditionsderived from the above mentioned first step to fourth step.

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S (λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 48]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 49]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).

It is preferable that Φ_(elm)(λ) does not satisfy at least one of thefollowing Condition 3 and Condition 4, and φ_(SSL)(λ) satisfies bothCondition 3 and Condition 4. Condition 3 and Condition 4 are also theconditions derived from the above mentioned first step to fourth step.

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by the formula(3) satisfies formula (4) below and1.0≦SAT _(av)≦7.0  (4)if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

According to the examination of the results of Reference Example 1 andExample 9 and the results of Reference Example 2 and Example 11, thelight-emitting devices according to Example 9 and Example 11, which canimplement an even better appearance of colors, can be implementedrespectively by disposing an appropriate control element in thelight-emitting device (regarded as a light-emitting element) accordingto Reference Example 1 and Reference Example 2, which can implement agood appearance of colors.

In other words, in a light-emitting device having a light-emittingelement, which includes a semiconductor light-emitting element, and acontrol element, if λ(nm) is a wavelength, Φ_(elm)(λ) is the spectralpower distribution of light emitted from this light-emitting element inthe main radiant direction, φ_(SSL) (λ) is the spectral powerdistribution of light emitted from the light-emitting device in the mainradiant direction, Φ_(elm)(λ) satisfies both the above mentionedCondition 1 and Condition 2, and φ_(SSL)(λ) satisfies both the abovementioned Condition 1 and Condition 2, the light-emitting device(light-emitting element), which can implemented a good appearance ofcolors, becomes a light-emitting device which can implement an evenbetter appearance of colors by the control unit.

Particularly, even in a semiconductor light-emitting device in whichappearance of colors is excellent when used for an illumination purpose,the appearance of colors can be further adjusted according to the tasteof the user.

It is preferable that Φ_(elm)(λ) satisfies both Condition 3 andCondition 4, and φ_(SSL)(λ) satisfies both Condition 3 and Condition 4.

On the other hand, the method for manufacturing the light-emittingdevice according to the second embodiment of the fifth invention of thepresent invention can be derived from the above mentioned experimentresults.

In other words, this is a method for manufacturing a light-emittingdevice having: a light-emitting element which includes a semiconductorlight-emitting element; and a control element, the manufacturing methodcomprising: a step of preparing a first light-emitting device having thelight-emitting element; and a step of manufacturing a secondlight-emitting device by disposing the control element so that at leasta part of the light emitted from the first light-emitting device in themain radiant direction transmits through, and when λ(nm) is awavelength, Φ_(elm)(λ) is a spectral power distribution of a lightemitted from the first light-emitting device in the main radiantdirection, and φ_(SSL)(λ) is a spectral power distribution of a lightemitted from the second light-emitting device in the main radiantdirection, Φ_(elm)(λ) does not satisfy at least one of the abovementioned Condition 1 and Condition 2, and φ_(SSL)(λ) satisfies both theabove mentioned Condition 1 and Condition 2.

Particularly, manufacturing the light-emitting device that can implementa good appearance of colors according to this embodiment, by executing astep of disposing a specific control element in an LED lighting devicewhich is already on the market and does not implement a good appearanceof colors, is within the technical scope of the second embodiment of thefirst, second, fourth and fifth inventions of the present invention.

The above mentioned manufacturing method is also a method formanufacturing a light-emitting device having: a light-emitting elementwhich includes a semiconductor light-emitting element; and a controlelement, the manufacturing method comprising: a step of preparing afirst light-emitting device having a light-emitting element; and a stepof manufacturing a second light-emitting device by disposing the controlelement so that at least a part of the light emitted from the firstlight-emitting device in the main radiant direction transmits through,and when λ(nm) is a wavelength, Φ_(elm)(λ) is a spectral powerdistribution of a light emitted from the first light-emitting device inthe main radiant direction, and φ_(SSL)(λ) is a spectral powerdistribution of a light emitted from the second light-emitting device inthe main radiant direction, Φ_(elm)(λ) satisfies both the abovementioned Condition 1 and Condition 2, and φ_(SSL)(λ) satisfies both theabove mentioned Condition 1 and Condition 2.

Further, the method for designing the light-emitting device according tothe second embodiment of the second invention of the present inventioncan be derived from the above mentioned experiment results in the samemanner.

In other words, this is a method for designing a light-emitting devicehaving: a light-emitting element which includes a semiconductorlight-emitting element; and a control element, and when λ(nm) is awavelength, Φ_(elm)(λ) is a spectral power distribution of a lightemitted from the first light-emitting element in the main radiantdirection, and φ_(SSL)(λ) is a spectral power distribution of a lightemitted from the light-emitting device in the main radiant direction, itis designed that Φ_(elm)(λ) does not satisfy at least one of the abovementioned Condition 1 and Condition 2, and φ_(SSL)(λ) satisfies both theabove mentioned Condition 1 and Condition 2.

The above mentioned design method is also a method for designing alight-emitting device: having a light-emitting element which includes asemiconductor light-emitting element; and a control element, and whenλ(nm) is a wavelength, Φ_(elm)(λ) is a spectral power distribution of alight emitted from the first light-emitting element in the main radiantdirection, and φ_(SSL)(λ) is a spectral power distribution of a lightemitted from the light-emitting device in the main radiant direction, itis designed that Φ_(elm)(λ) satisfies both the above mentioned Condition1 and Condition 2, and φ_(SSL)(λ) also satisfies both the abovementioned Condition 1 and Condition 2.

Further, the illumination method according to the second embodiment ofthe fourth invention of the present invention can be derived from theabove mentioned experiment results in the same manner.

In other words, the illumination method is an illumination methodcomprising:

illuminated objects preparation step of preparing illuminated objects;and

an illumination step of illuminating the objects by light emitted from alight-emitting devices which includes a semiconductor light-emittingelement as a light-emitting element and a control element,

in the illumination step,

when light emitted from the light-emitting element illuminate theobjects, the objects are illuminated so that the light measured at aposition of the objects does not satisfy at least any one of <1>, <2>and <3> below, and

when light emitted from the light-emitting device illuminate theobjects, the objects are illuminated so that the light measured at aposition of the objects satisfies all <1>, <2> and <3> below:

The following <1>, <2> and <3> are conditions derived from the abovementioned first step to fourth step.

<1> a distance D_(uvSSL) from a black-body radiation locus as defined byANSI C78.377 of the target light measured at the position of the objectssatisfies −0.0350≦D_(uv)≦−0.0040;

<2> if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light measured at theposition of the objects are respectively denoted by a*_(n) and b*_(n)(where n is a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the target light measured at theposition of the objects are respectively denoted by a*_(nref) andb*_(nref) (where n is a natural number from 1 to 15), then eachsaturation difference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by the formula(3) satisfies formula (4) below and1.0≦SAT _(av)≦7.0  (4)

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference ΔC_(max)−ΔC_(min) between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8Δ|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

<3> if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light measured at the position of the objects are denoted byθ_(n) (degrees) (where n is a natural number from 1 to 15), and

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the target light measured at the position of theobjects are denoted by θ_(nref) (degrees) (where n is a natural numberfrom 1 to 15), then an absolute value of each difference in hue angles|Δh_(n)| satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

here Δh_(n)=θ_(n)−θ_(nref).

It is preferable that the light emitted from the light emittingapparatus satisfies <4>. <4> is also a condition derived from the abovementioned first step to fourth step.

<4> if a spectral power distribution of the target light measured at theposition of the objects is denoted by φ(λ), a spectral powerdistribution of a reference light that is selected according to T (K) ofthe target light measured at the position of the objects is denoted byφ_(ref) (λ), tristimulus values of the the target light measured at theposition of the objects are denoted by (X, Y, Z), and tristimulus valuesof the reference light that is selected according to T (K) of the targetlight measured at the position of the objects are denoted by (X_(ref),Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S (λ) of target lightmeasured at the position of the objects, a normalized spectral powerdistribution S_(ref) (λ) of a reference light that is selected accordingto T (K) of the target light measured at the position of the objects,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/Y,S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S(λ) and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 50]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 51]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).

In addition, the illumination method is an illumination methodcomprising: illuminated objects preparation step of preparingilluminated objects; and an illumination step of illuminating theobjects by light emitted from a light-emitting devices which includes asemiconductor light-emitting element as a light-emitting element and acontrol element, in the illumination step, when light emitted from thelight-emitting element illuminate the objects, the objects areilluminated so that the light measured at a position of the objectssatisfies all <1>, <2> and <3> above, and when light emitted from thelight-emitting device illuminate the objects, the objects areilluminated so that the light measured at a position of the objects alsosatisfies all <1>, <2> and <3> above. It is preferable that the lightemitted from the light-emitting device satisfies <4> duringillumination.

While a favorable embodiment for implementing the light-emitting deviceand the illumination method that implement a natural, vivid, highlyvisible and comfortable appearance of colors and appearance of objectsas if the objects are seen outdoors according to the first embodiment ofthe first and fourth inventions of the present invention will bedescribed below, it is to be understood that modes for implementing thelight-emitting device and the illumination method according to the firstembodiment of the first and fourth inventions of the present inventionare not limited to those used in the following description.

While a favorable embodiment for implementing the light-emitting device,the method for manufacturing the light-emitting device, the method fordesigning the light-emitting device and the illumination methodaccording to the second embodiment of the first, fifth, second andfourth inventions of the present invention will be described below, itis to be understood that modes for implementing the light-emittingdevice, the method for manufacturing the light-emitting device, themethod for designing the light-emitting device and the illuminationmethod according to the second embodiment of the first, fifth, secondand fourth inventions of the present invention are not limited to thoseused in the following description.

In the illumination method according to the first embodiment of thefourth invention of the present invention, no restrictions are placed onconfigurations, materials, and the like of the light-emitting device aslong as a photometric property of test light which is irradiated on anilluminated object and which becomes a color stimulus is in anappropriate range and, at the same time, a difference between colorappearances of the 15 color samples when illumination by calculationalreference light is assumed and color appearances of the 15 color sampleswhen illumination by an actually measured test light spectral powerdistribution is assumed is in an appropriate range.

With the light-emitting device according to the first embodiment of thefirst invention of the present invention, no restrictions are placed onconfigurations, materials, and the like of the light-emitting device aslong as a radiometric property and a photometric property of test lightwhich is irradiated from the light-emitting device in a main radiantdirection and which becomes a color stimulus with respect to anilluminated object are in appropriate ranges.

With the light-emitting device, the method for manufacturing thelight-emitting device and the method for designing the light-emittingdevice according to the second embodiment of the first, fifth and secondinventions of the present invention, no restrictions are placed onconfigurations, materials, and the like of the light-emitting device aslong as a radiometric property and a photometric property of test lightwhich is irradiated from the light-emitting device in a main radiantdirection and which becomes a color stimulus with respect to anilluminated object are in appropriate ranges.

A light-emitting device for implementing the illumination method or thelight-emitting device according to the first embodiment of the fourth orthe first invention of the present invention such as an illuminationlight source, alighting fixture including the illumination light source,or a lighting system including the illumination light source or thelighting fixture includes at least one semiconductor light-emittingelement that is a light-emitting element. For example, the illuminationlight source including the semiconductor light-emitting element may beconfigured such that a plurality of semiconductor light-emittingelements of different types such as blue, green, and red is incorporatedin one illumination light source or may be configured such that a bluesemiconductor light-emitting element is included in one illuminationlight source, a green semiconductor light-emitting element is includedin another illumination light source, and a red semiconductorlight-emitting element is included in yet another illumination lightsource, whereby the semiconductor light-emitting elements are integratedwith a lens, a reflecting mirror, a drive circuit, and the like in alight fixture and provided to a lighting system. Furthermore, in a casewhere one illumination light source is included in one lighting fixtureand an individual semiconductor light-emitting element is incorporatedin the illumination light source, even if the illumination method or thelight-emitting device according to the first embodiment of the fourth orthe first invention of the present invention cannot be implemented as anindividual illumination light source or an individual lighting fixture,a lighting system may be configured such that light radiated as thelighting system satisfies desired characteristics at a position of anilluminated object due to additive color mixing with light from adifferent lighting fixture that exists in the lighting system or thelighting system may be configured such that light in a main radiantdirection among light radiated as the lighting system satisfies desiredcharacteristics. In any mode, light as a color stimulus which isultimately irradiated on an illuminated object or light in a mainradiant direction among light emitted from the light-emitting deviceneed only satisfy appropriate conditions according to the firstembodiment of the first to fifth inventions of the present invention.

A light-emitting device for implementing the light-emitting device, themethod for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention such as an illumination light source, alighting fixture including the illumination light source, or a lightingsystem including the illumination light source or the lighting fixtureincludes at least a light-emitting element and at least a controlelement. The light-emitting element preferably includes semiconductorlight-emitting element. For example, the illumination light sourceincluding the semiconductor light-emitting element may be configuredsuch that a plurality of semiconductor light-emitting elements ofdifferent types such as blue, green, and red is incorporated in oneillumination light source or may be configured such that a bluesemiconductor light-emitting element is included in one illuminationlight source, a green semiconductor light-emitting element is includedin another illumination light source, and a red semiconductorlight-emitting element is included in yet another illumination lightsource, whereby the semiconductor light-emitting elements are integratedwith a filter, a lens, a reflecting mirror, a drive circuit, and thelike in a light fixture and provided to a lighting system. Furthermore,in a case where one illumination light source is included in onelighting fixture and an individual semiconductor light-emitting elementis incorporated in the illumination light source, even if theillumination method or the light-emitting device according to the secondembodiment of the fourth or the first invention of the present inventioncannot be implemented as an individual illumination light source or anindividual lighting fixture, a lighting system may be configured suchthat light radiated as the lighting system satisfies desiredcharacteristics at a position of an illuminated object due to additivecolor mixing with light from a different lighting fixture that exists inthe lighting system or the lighting system may be configured such thatlight in a main radiant direction among light radiated as the lightingsystem satisfies desired characteristics. In any mode, light in a mainradiant direction among light emitted from the light-emitting device orlight as a color stimulus which is ultimately irradiated on anilluminated object need only satisfy appropriate conditions according tothe second embodiment of the first, second, fourth and fifth inventionsof the present invention.

Hereinafter, characteristics will be described which are favorablyattained by the light-emitting device according to the first embodimentof the first to fourth inventions of the present invention that canachieve a color appearance or an object appearance that is as natural,vivid, highly visible, and comfortable as perceived outdoors on thebasis of satisfying the appropriate conditions described above.

Moreover, characteristics will be described which are favorably attainedby the light-emitting device according to the second embodiment of thefirst invention of the present invention, a light-emitting device forimplementing the method for manufacturing the light-emitting deviceaccording to the second embodiment of the fifth invention of the presentinvention, the method for designing the light-emitting device accordingto the second embodiment of the second invention of the presentinvention and the illumination method according to the second embodimentof the fourth invention of the present invention on the basis ofsatisfying the appropriate conditions described above.

The light-emitting device according to the first embodiment of the firstinvention of the present invention, a light-emitting device forimplementing the light-emitting device according to the secondembodiment of the first invention of the present invention, the methodfor manufacturing the light-emitting device according to the secondembodiment of the fifth invention of the present invention, the methodfor designing the light-emitting device according to the secondembodiment of the second invention of the present invention or theillumination method according to the second embodiment of the fourthinvention of the present invention favorably includes a light-emittingelement (light-emitting material) which has a peak within a shortwavelength range from Λ1 (380 nm) to Λ2 (495 nm), another light-emittingelement (light-emitting material) which has a peak within anintermediate wavelength range from Λ2 (495 nm) to Λ3 (590 nm), and yetanother light-emitting element (light-emitting material) which has apeak within a long wavelength range from Λ3 (590 nm) to 780 nm. This isbecause favorable color appearance can be readily achieved if intensityof each of the light-emitting elements can be individually set orcontrolled.

Therefore, the light-emitting device according to the first embodimentof the first invention of the present invention, the light-emittingdevice according to the second embodiment of the first invention of thepresent invention, a light-emitting device for implementing the methodfor manufacturing the light-emitting device according to the secondembodiment of the fifth invention of the present invention, the methodfor designing the light-emitting device according to the secondembodiment of the second invention of the present invention or theillumination method according to the second embodiment of the fourthinvention of the present invention favorably includes at least one eachof light-emitting elements (light-emitting materials) which haveemission peaks in the three respective wavelength ranges describedabove, more favorably includes one light-emitting element(light-emitting material) in each of two wavelength ranges among thethree wavelength ranges and a plurality of light-emitting elements(light-emitting materials) in the one remaining wavelength range,extremely favorably includes one light-emitting element (light-emittingmaterial) in one wavelength range among the three wavelength ranges anda plurality of light-emitting elements (light-emitting materials) ineach of the two remaining wavelength ranges, and dramatically favorablyincludes a plurality of light-emitting elements (light-emittingmaterials) in all three wavelength ranges. This is because byincorporating light-emitting elements such that two or more peakwavelengths exist in one range, controllability of a spectral powerdistribution dramatically increases and, mathematically, a colorappearance of an illuminated object can be more easily controlled asdesired.

Therefore, in an actual light-emitting device that uses a semiconductorlight-emitting element as a phosphor excitation light source, favorably,there are two types of phosphors in one light-emitting device and thereare peak wavelengths in each of the three wavelength ranges includingthe wavelength of the semiconductor light-emitting element. In addition,it is even more favorable to have three types of phosphors and have twolight-emitting elements incorporated in at least one range among thethree wavelength regions including the wavelength of the semiconductorlight-emitting element. From this perspective, it is extremely favorableto have four or more types of phosphors and dramatically favorable tohave five types of phosphors. In particular, if there are six or moretypes of phosphors in one light source, spectrum controllabilityinversely declines due to mutual absorption among the phosphors andtherefore becomes unfavorable. Furthermore, from a different perspectiveof realizing a simple light-emitting device, only one type of phosphormay be used and a light-emitting device may be configured with a totalof two types of light-emitting elements including an emission peak ofthe semiconductor light-emitting element.

This also applies to a case where an actual light-emitting device isconfigured using only semiconductor light-emitting elements withdifferent peak wavelengths. In other words, from the perspective ofrealizing a favorable spectral power distribution, the number ofdifferent types of semiconductor light-emitting elements in one lightsource is favorably three or more, more favorably four or more,extremely favorably five or more, and dramatically favorably six ormore. Having seven or more different types creates a hassle whenmounting on a light source or the like and therefore becomesunfavorable. Furthermore, from a different perspective of realizing asimple light-emitting device, a light-emitting device may be configuredwith two types of semiconductor light-emitting elements.

Moreover, semiconductor light-emitting elements and phosphors can bemixed and mounted at will. For example, a blue light-emitting elementand two types of phosphors (green and red) may be mounted in one lightsource, or a blue light-emitting element and three types of phosphors(green, red 1, and red 2) may be mounted in one light source.Furthermore, a purple light-emitting element and four types of phosphors(blue, green, red 1, and red 2) may be mounted in one light source.Moreover, one light source may incorporate a portion mounted with a bluelight-emitting element and two types of phosphors (green and red) and aportion mounted with a purple light-emitting element and three types ofphosphors (blue, green, and red).

From the perspective of controlling intensity of peak portions orintensity of valleys between peaks or, in other words, the perspectiveof forming an appropriate concave and/or convex shape in a spectralpower distribution, light-emitting elements (light-emitting materials)in each of the three wavelength ranges favorably include at least onelight-emitting element with a relatively narrow band. Conversely, it isdifficult to form an appropriate concave and/or convex shape in aspectral power distribution using only light-emitting elements withwidths comparable to widths of the three respective wavelength ranges.Therefore, in the light-emitting device according to the firstembodiment of the first invention of the present invention, thelight-emitting device according to the second embodiment of the firstinvention of the present invention, a light-emitting device forimplementing the method for manufacturing the light-emitting deviceaccording to the second embodiment of the fifth invention of the presentinvention, the method for designing the light-emitting device accordingto the second embodiment of the second invention of the presentinvention or the illumination method according to the second embodimentof the fourth invention of the present invention, it is favorable toinclude at least one relatively narrow band light-emitting element.However, more favorably, two ranges among the three respectivewavelength ranges include a relatively narrow band light-emittingelement and, even more favorably, all of the three respective wavelengthranges include a relatively narrow band light-emitting element. In thiscase, while a relatively narrow band light-emitting element may itselfindividually constitute a light-emitting element in a given wavelengthregion, more favorably, a plurality of types of relatively narrow bandlight-emitting elements exist in the wavelength region and, equally morefavorably, a relatively narrow band light-emitting element and arelatively broad band light-emitting element coexist in the wavelengthregion.

Moreover, a “relatively narrow band” as used herein refers to afull-width at half-maximum of a light-emitting element (light-emittingmaterial) being equal to or less than ⅔ of 115 nm, 95 nm, and 190 nmwhich are respective range widths of the short wavelength range (380 nmto 495 nm), the intermediate wavelength range (495 nm to 590 nm), andthe long wavelength range (590 nm to 780 nm). In addition, among arelatively narrow band light-emitting element, a full-width athalf-maximum of the light-emitting element with respect to therespective range widths is favorably ½ or less, more favorably ⅓ orless, extremely favorably ¼ or less, and dramatically favorably ⅕ orless. Furthermore, since a narrow band spectrum that is excessivelynarrow may result in a case where desired characteristics cannot berealized unless a large number of different types of light-emittingelements are mounted in a light-emitting device, the full-width athalf-maximum is favorably 2 nm or more, more favorably 4 nm or more,extremely favorably 6 nm or more, and dramatically favorably 8 nm ormore.

From the perspective of realizing a desired spectral power distribution,combining relatively narrow band light-emitting elements (light-emittingmaterials) is favorable since a concave and/or a convex shape can bemore easily formed in the spectral power distribution and the indexA_(cg), the luminous efficacy of radiation K (lm/W), and the like whoseappropriate ranges have become apparent through the visual experimentscan be more easily set to desired values. In addition, it is favorableto treat light as a color stimulus and incorporate a relatively narrowband light-emitting element among the light-emitting elements since adifference between color appearances of the 15 color samples whenillumination by the light-emitting device is assumed and colorappearances when illumination by calculational reference light isassumed can be more conveniently used to perform saturation control and,in particular, to set |Δh_(n)|, SAT_(av), ΔC_(n), |ΔC_(max)−ΔC_(min)|,and the like whose appropriate ranges have become apparent through thevisual experiments within appropriate numerical value ranges.Furthermore, it is favorable to use a relatively narrow band phosphorsince D_(uv) control can be performed more easily than when using abroad band phosphor.

In the light-emitting device according to the first embodiment of thefirst invention of the present invention, the following light-emittingmaterials, phosphor materials, and semiconductor light-emitting elementsare favorably incorporated in the light-emitting device aslight-emitting elements.

In the light-emitting device, the method for manufacturing thelight-emitting device, the method for designing the light-emittingdevice, and the illumination method according to the second embodimentof the first, fifth, second and fourth inventions of the presentinvention, a part of the broad band spectral power distribution emittedfrom the emitting element is absorbed, reflected or collected by thecontrol element, whereby a spectral power distribution of which band isnarrower than the light-emitting element can be implemented, which ispreferable.

In the light-emitting device, the method for manufacturing thelight-emitting device, the method for designing the light-emittingdevice and the illumination method according to the second embodiment ofthe first, fifth, second and forth inventions of the present invention,the following light-emitting materials, phosphor materials, andsemiconductor light-emitting elements are favorably incorporated in thelight-emitting device as light-emitting elements.

First, in the short wavelength range from Λ1 (380 nm) to Λ2 (495 nm)among the three wavelength ranges, light emitted from all light sourcescan be included, such as thermal emission light from a hot filament orthe like, electric discharge emission light from a fluorescent tube, ahigh-pressure sodium lamp, or the like, stimulated emission light from alaser or the like, spontaneous emission light from a semiconductorlight-emitting element, and spontaneous emission light from a phosphor.Among the above, emission of light from a photoexcited phosphor,emission of light from a photoexcited semiconductor light-emittingelement, and emission of light from a photoexcited semiconductor laserare favorable due to their small sizes, high energy efficiency, andtheir ability to emit light in a relatively narrow band.

Specifically, the following is favorable.

Favorable examples of a semiconductor light-emitting element include apurple light-emitting element (with a peak wavelength of around 395 nmto 420 nm), a bluish purple light-emitting element (with a peakwavelength of around 420 nm to 455 nm), or a blue light-emitting element(with a peak wavelength of around 455 nm to 485 nm) in which anIn(Al)GaN material formed on a sapphire substrate or a GaN substrate isincluded in an active layer structure. Furthermore, a bluelight-emitting element (with a peak wavelength of around 455 nm to 485nm) in which a Zn(Cd)(S)Se material formed on a GaAs substrate isincluded in an active layer structure is also favorable.

Moreover, a spectral power distribution or a peak wavelength of aradiant flux produced by a light-emitting element (light-emittingmaterial) such as a semiconductor light-emitting element or a phosphornormally fluctuates slightly depending on ambient temperature, a heatdissipation environment of the light-emitting device including a packageand a fixture, injected current, circuit architecture and, in somecases, deterioration or the like. Therefore, a semiconductorlight-emitting element with a peak wavelength of 418 nm under a certaindrive condition may exhibit a peak wavelength of, for example, 421 nmwhen temperature of ambient environment rises.

The same applies to a spectral power distribution or a peak wavelengthof a radiant flux produced by light-emitting elements (light-emittingmaterials) such as the semiconductor light-emitting elements andphosphors described below.

The active layer structure may be any of a multiple quantum wellstructure in which a quantum well layer and a barrier layer arelaminated, a single or a double heterostructure including a relativelythick active layer and a barrier layer (or a clad layer), and a homojunction constituted by a single pn junction.

In particular, when the active layer includes an In(Al)GaN material, abluish purple light-emitting element and a purple light-emitting elementin which In concentration decreases in the active layer structure ascompared to a blue light-emitting element are favorable since emissionwavelength fluctuation due to segregation by In decreases and afull-width at half-maximum of the emission spectrum becomes narrower. Inaddition, a bluish purple light-emitting element and a purplelight-emitting element are favorable because wavelengths are positionedcloser to a relatively outer side (short wavelength-side) of thewavelength range from 380 nm to 495 nm and D_(uv) can be easilycontrolled. In other words, a semiconductor light-emitting elementhaving an emission peak in the short wavelength range from Λ1 (380 nm)to Λ2 (495 nm) in the first to fifth inventions of the present inventionis favorably a blue light-emitting element (with a peak wavelength ofaround 455 nm to 485 nm), more favorably a bluish purple light-emittingelement (with a peak wavelength of around 420 nm to 455 nm) with ashorter wavelength, and extremely favorably a purple light-emittingelement (with a peak wavelength of around 395 nm to 420 nm) with ashorter wavelength. Furthermore, it is also favorable to use a pluralityof types of these light-emitting elements. Furthermore, it is alsofavorable to use a plurality of types of these light-emitting elements.

Moreover, a semiconductor laser is also favorably used as thelight-emitting element and, for the same reasons as described above, thesemiconductor laser is favorably a blue semiconductor laser (with anemission wavelength of around 455 nm to 485 nm), more favorably a bluishpurple semiconductor laser (with an emission wavelength of around 420 nmto 455 nm) with a longer wavelength, and extremely favorably a purplesemiconductor laser (with an emission wavelength of around 395 nm to 420nm) with a longer wavelength.

With a short wavelength range semiconductor light-emitting element thatis used in the light-emitting device, the method for manufacturing thelight-emitting device, the method for designing the light-emittingdevice or the illumination method according to the second embodiment ofthe first, fifth, second or fourth invention of the present invention, afull-width at half-maximum of an emission spectrum of the semiconductorlight-emitting element is favorably narrow. From this perspective, thefull-width at half-maximum of the semiconductor light-emitting elementused in the short wavelength range is favorably 45 nm or less, morefavorably 40 nm or less, extremely favorably 35 nm or less, anddramatically favorably 30 nm or less. On the other hand, since anexcessively narrow band spectrum may result in a case where desiredcharacteristics cannot be realized unless a large number of differenttypes of light-emitting elements are mounted in a light-emitting device,the full-width at half-maximum of the semiconductor light-emittingelement used in the short wavelength range is favorably 2 nm or more,more favorably 4 nm or more, extremely favorably 6 nm or more, anddramatically favorably 8 nm or more.

Since the short wavelength range semiconductor light-emitting elementthat is used in the light-emitting device according to the firstembodiment of the first invention of the present invention, and thelight-emitting device, the method for manufacturing the light-emittingdevice, the method for designing the light-emitting device or theillumination method according to the second embodiment of the first,fifth, second or fourth invention of the present invention favorablyincludes an In(Al)GaN material in an active layer structure, thesemiconductor light-emitting element is favorably a light-emittingelement formed on a sapphire substrate or a GaN substrate. Inparticular, the degree of In segregation in the active layer of alight-emitting element formed on a GaN substrate is more favorable thanwhen formed on a sapphire substrate. This is dependent on the degree oflattice matching between the substrate and active layer structurematerial. Therefore, since the full-width at half-maximum of anIn(Al)GaN emission spectrum on a GaN substrate can be set narrower, adramatic synergistic effect with the first to fifth inventions of thepresent invention can be expected and is therefore extremely favorable.Furthermore, even among light-emitting elements on a GaN substrate,elements formed on a semi-polar surface or a non-polar surface areparticularly favorable. This is because a decrease in a piezoelectricpolarization effect in a crystal growth direction causes an increase inspatial overlapping of electrons' and holes' wave function in a quantumwell layer and, in principle, an increase in radiation efficiency and anarrower band spectrum can be achieved. Therefore, by using asemiconductor light-emitting element on a semi-polar or non-polar GaNsubstrate, a dramatic synergistic effect with the first to fifthinventions of the present invention can be expected and is thereforeextremely favorable.

In addition, as far as substrate thickness is concerned, the substrateis favorably either thick or completely separated from the semiconductorlight-emitting element. In particular, when creating a short wavelengthrange semiconductor light-emitting element on a GaN substrate, in orderto facilitate light extraction from side walls of the GaN substrate, thesubstrate is favorably thick and is 100 μm or more, more favorably 200μm or more, extremely favorably 400 μm or more, and dramaticallyfavorably 600 μm or more. On the other hand, for convenience of creatingelements, the substrate thickness is favorably 2 mm or less, morefavorably 1.8 mm or less, extremely favorably 1.6 mm or less, anddramatically favorably 1.4 mm or less.

Meanwhile, when creating a light-emitting element on a sapphiresubstrate or the like, the substrate is favorably separated using amethod such as laser lift-off. Such a configuration reduces stressacting on the quantum well layer which facilitates widening of bandwidthdue to an extreme lattice mismatch with the substrate and, as a result,a narrower band spectrum of the light-emitting element can be achieved.Therefore, with a light-emitting element separated from a sapphiresubstrate or the like, a dramatic synergistic effect with the first tofifth inventions of the present invention can be expected and istherefore extremely favorable.

With a short wavelength range phosphor material that is used in thelight-emitting device according to the first embodiment of the firstinvention of the present invention, and the light-emitting device, themethod for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention, a full-width at half-maximum of the phosphormaterial is favorably narrow. From this perspective, the full-width athalf-maximum of an emission spectrum of the phosphor material used inthe short wavelength range when photoexcited at room temperature isfavorably 90 nm or less, more favorably 80 nm or less, extremelyfavorably 70 nm or less, and dramatically favorably 60 nm or less. Onthe other hand, since an excessively narrow band spectrum may result ina case where desired characteristics cannot be realized unless a largenumber of different types of light-emitting elements are mounted in alight-emitting device, the full-width at half-maximum of the phosphormaterial used in the short wavelength range is favorably 2 nm or more,more favorably 4 nm or more, extremely favorably 6 nm or more, anddramatically favorably 8 nm or more.

With a short wavelength range phosphor material, in consideration ofexciting the phosphor material and D_(uv) controllability, the phosphormaterial favorably has a peak wavelength in the following ranges. In acase of light excitation, the peak wavelength favorably ranges from 455nm to 485 nm and more favorably has a shorter wavelength from 420 nm to455 nm. On the other hand, in a case of electron beam excitation, thepeak wavelength favorably ranges from 455 nm to 485 nm, more favorablyhas a shorter wavelength from 420 nm to 455 nm, and extremely favorablyhas a shorter wavelength from 395 nm to 420 nm.

As for specific examples of the short wavelength range phosphor materialused in the light-emitting device according to the first embodiment ofthe first invention of the present invention, and the light-emittingdevice, the method for manufacturing the light-emitting device, themethod for designing the light-emitting device or the illuminationmethod according to the second embodiment of the first, fifth, second orfourth invention of the present invention, while any phosphor materialsatisfying the full-width at half-maximum described above can befavorably used, one specific example is a blue phosphor which uses Eu²⁺as an activator and a crystal constituted by alkaline-earth aluminate oralkaline-earth halophosphate as a host. More specifically, examplesinclude a phosphor represented by the following general formula (5), aphosphor represented by the following general formula (5)′, (Sr,Ba)₃MgSi₂O₈:Eu²⁺, and (Ba, Sr, Ca, Mg)Si₂O₂N₂:Eu.(Ba,Sr,Ca)MgAl₁₀O₁₇:Mn,Eu  (5)(An alkaline-earth aluminate phosphor represented by the general Formula(5) is referred to as a BAM phosphor).Sr_(a)Ba_(b)Eu_(x)(PO₄)_(c)X_(d)  (5)′

(In the general formula (5)′, X is Cl. In addition, c, d, and x arenumbers satisfying 2.7≦c≦3.3, 0.9≦d≦1.1, and 0.3≦x≦1.2. Furthermore, aand b satisfy conditions represented by a+b=5−x and 0≦b/(a+b)≦0.6.)(Among alkaline-earth halophosphate phosphors represented by generalFormula (5)′, those containing Ba are referred to as SBCA phosphors andthose not containing Ba are referred to as SCA phosphors).

Favorable examples include a BAM phosphor, a SBCA phosphor, and a SCAphosphor, which are the phosphors described above, as well as a Ba—SIONphosphor ((Ba, Sr, Ca, Mg)Si₂O₂N₂:Eu) and a (Sr, Ba)₃MgSi₂O₈:Eu²⁺phosphor.

Next, in the intermediate wavelength range from Λ2 (495 nm) to Λ3 (590nm) among the three wavelength ranges, light emitted from all lightsources can be included, such as thermal emission light from a hotfilament or the like, electric discharge emission light from afluorescent tube, a high-pressure sodium lamp, or the like, stimulatedemission light from a laser or the like including second-order harmonicgeneration (SHG) using a non-linear optical effect or the like,spontaneous emission light from a semiconductor light-emitting element,and spontaneous emission light from a phosphor. Among the above,emission of light from a photoexcited phosphor, emission of light from aphotoexcited semiconductor light-emitting element, emission of lightfrom a photoexcited semiconductor laser, and emission of light from aphotoexcited SHG laser are favorable due to their small sizes, highenergy efficiency, and their ability to emit light in a relativelynarrow band.

Specifically, the following is favorable.

Favorable examples of a semiconductor light-emitting element include agreenish blue light-emitting element (with a peak wavelength of around495 nm to 500 nm), a green light-emitting element (with a peakwavelength of around 500 nm to 530 nm), a yellowish green light-emittingelement (with a peak wavelength of around 530 nm to 570 nm), or a yellowlight-emitting element (with a peak wavelength of around 570 nm to 580nm) in which an In(Al)GaN material on a sapphire substrate or a GaNsubstrate is included in an active layer structure. In addition, ayellowish green light-emitting element (with a peak wavelength of around530 nm to 570 nm) due to GaP on a GaP substrate or a yellowlight-emitting element (with a peak wavelength of around 570 nm to 580nm) due to GaAsP on a GaP substrate is also favorable. Furthermore, ayellow light-emitting element (with a peak wavelength of around 570 nmto 580 nm) due to AlInGaP on a GaAs substrate is also favorable.

The active layer structure may be any of a multiple quantum wellstructure in which a quantum well layer and a barrier layer arelaminated, a single or a double heterostructure including a relativelythick active layer and a barrier layer (or a clad layer), and a homojunction constituted by a single pn junction.

In particular, when using an In(Al)GaN material, a yellowish greenlight-emitting element, a green light-emitting element, and a greenishblue light-emitting element in which In concentration decreases in theactive layer structure as compared to a yellow light-emitting elementare favorable since emission wavelength fluctuation due to segregationby In decreases and a full-width at half-maximum of the emissionspectrum becomes narrower. In other words, a semiconductorlight-emitting element having an emission peak in the intermediatewavelength range from Λ2 (495 nm) to Λ3 (590 nm) in the first to fifthinventions of the present invention is favorably a yellow light-emittingelement (with a peak wavelength of around 570 nm to 580 nm), morefavorably a yellowish green light-emitting element (with a peakwavelength of around 530 nm to 570 nm) with a shorter wavelength,extremely favorably a green light-emitting element (with a peakwavelength of around 500 nm to 530 nm) with a shorter wavelength, anddramatically favorably a greenish blue light-emitting element (with apeak wavelength of around 495 nm to 500 nm).

Furthermore, a semiconductor laser, an SHG laser which converts anemission wavelength of a semiconductor laser using a non-linear opticaleffect, and the like are also favorably used as a light-emittingelement. For the same reasons as described above, an emission wavelengthis favorably within a yellow range (with a peak wavelength of around 570nm to 580 nm), more favorably within a yellowish green range (with apeak wavelength of around 530 nm to 570 nm) with a shorter wavelength,extremely favorably within a green range (with a peak wavelength ofaround 500 nm to 530 nm) with a shorter wavelength, and dramaticallyfavorably within a greenish blue range (with a peak wavelength of around495 nm to 500 nm).

With an intermediate wavelength range semiconductor light-emittingelement that is used in the light-emitting device according to the firstembodiment of the first invention of the present invention, and thelight-emitting device, the method for manufacturing the light-emittingdevice, the method for designing the light-emitting device or theillumination method according to the second embodiment of the first,fifth, second or fourth invention of the present invention, a full-widthat half-maximum of an emission spectrum of the semiconductorlight-emitting element is favorably narrow. From this perspective, thefull-width at half-maximum of the semiconductor light-emitting elementused in the intermediate wavelength range is favorably 75 nm or less,more favorably 60 nm or less, extremely favorably 50 nm or less, anddramatically favorably 40 nm or less. On the other hand, since anexcessively narrow band spectrum may result in a case where desiredcharacteristics cannot be realized unless a large number of differenttypes of light-emitting elements are mounted in a light-emitting device,the full-width at half-maximum of the semiconductor light-emittingelement used in the intermediate wavelength range is favorably 2 nm ormore, more favorably 4 nm or more, extremely favorably 6 nm or more, anddramatically favorably 8 nm or more.

When the intermediate wavelength range semiconductor light-emittingelement that is used in the light-emitting device according to the firstembodiment of the first invention of the present invention, and thelight-emitting device, the method for manufacturing the light-emittingdevice, the method for designing the light-emitting device or theillumination method according to the second embodiment of the first,fifth, second or fourth invention of the present invention includes anIn(Al)GaN material in an active layer structure, the semiconductorlight-emitting element is favorably a light-emitting element formed on asapphire substrate or a GaN substrate. In addition, a light-emittingelement formed on a GaN substrate is particularly favorable. This is dueto the fact that while In must be introduced into the active layerstructure in a relatively large amount when creating an InAlGaN elementin the intermediate wavelength range, an InAlGaN element formed on a GaNsubstrate reduces a piezoelectric effect attributable to a difference inlattice constants from the substrate and enables suppression of spatialseparation of electrons/holes when injecting a carrier into a quantumwell layer as compared to an InAlGaN element formed on a sapphiresubstrate. As a result, a full-width at half-maximum of the emissionwavelength can be narrowed. Therefore, in the first to fifth inventionsof the present invention, with an intermediate wavelength rangesemiconductor light-emitting element on a GaN substrate, a dramaticsynergistic effect can be expected and is therefore favorable.Furthermore, even among light-emitting elements on a GaN substrate,elements formed on a semi-polar surface or a non-polar surface isparticularly favorable. This is because a decrease in a piezoelectricpolarization effect in a crystal growth direction causes an increase inspatial overlapping of electrons' and holes' wave function in a quantumwell layer and, in principle, an increase in luminous efficiency and anarrower band spectrum can be achieved. Therefore, by using asemiconductor light-emitting element on a semi-polar or non-polar GaNsubstrate, a dramatic synergistic effect with the first to fifthinventions of the present invention can be expected and is thereforeextremely favorable.

With all semiconductor light-emitting elements, regardless of the typeof substrate on which the semiconductor light-emitting element isformed, the substrate is favorably either thick or completely removed.

In particular, when creating an intermediate wavelength rangesemiconductor light-emitting element on a GaN substrate, in order tofacilitate light extraction from side walls of the GaN substrate, thesubstrate is favorably thick and is 100 μm or more, more favorably 200μm or more, extremely favorably 400 μm or more, and dramaticallyfavorably 600 μm or more. On the other hand, for convenience of creatingelements, the substrate thickness is favorably 2 mm or less, morefavorably 1.8 mm or less, extremely favorably 1.6 mm or less, anddramatically favorably 1.4 mm or less.

In addition, the same applies when creating an intermediate wavelengthrange semiconductor light-emitting element on a GaP substrate and, inorder to facilitate light extraction from side walls of the GaPsubstrate, the substrate is favorably thick and is 100 μm or more, morefavorably 200 μm or more, extremely favorably 400 μm or more, anddramatically favorably 600 μm or more. On the other hand, forconvenience of creating elements, the substrate thickness is favorably 2mm or less, more favorably 1.8 mm or less, extremely favorably 1.6 mm orless, and dramatically favorably 1.4 mm or less.

Meanwhile, in a case of an AlInGaP material formed on a GaAs substrate,light in the emission wavelength range is absorbed due to a bandgap ofthe substrate being smaller than a bandgap of the material constitutingthe active layer structure. Therefore, as far as substrate thickness isconcerned, the substrate is favorably thin or completely separated fromthe semiconductor light-emitting element.

In addition, when creating a light-emitting element on a sapphiresubstrate or the like, the substrate is favorably separated using amethod such as laser lift-off. Such a configuration reduces stressacting on the quantum well layer which causes widening of bandwidth dueto an extreme lattice mismatch with the substrate and, as a result, anarrower band spectrum of the light-emitting element can be achieved.Therefore, with a semiconductor light-emitting element separated from asapphire substrate or the like, a dramatic synergistic effect with thefirst to fifth inventions of the present invention can be expected andis therefore extremely favorable.

As the intermediate wavelength range phosphor material used for thelight-emitting device according to the first embodiment of the firstinvention of the present invention, and the light-emitting device, themethod for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention, the following case is preferable.

For example, if a light-emitting element that emits a purple light, suchas a purple semiconductor light-emitting element, is used in a specificlight emitting area, and a blue phosphor is also used in the same lightemitting area, it is preferable that the phosphor, which emits light inthe intermediate wavelength range, emits light in a narrow band, becausethe spectral power distributions of the blue phosphor overlaps with theintermediate wavelength range phosphor material. This is because a moreappropriate concave portion (portion where the relative spectralintensity is low) can be formed in a range of 465 nm or more and 525 nmor less as the full-width at half-maximum of the intermediate wavelengthrange phosphor material is narrower, and creating this concave portionappropriately is critical to implement “a natural, vivid, highly visibleand comfortable appearance of colors and appearance of objects”.

In such a case, in consideration of D_(uv) controllability, a peakwavelength of an intermediate wavelength range phosphor materialfavorably ranges from 495 nm to 500 nm. A peak wavelength ranging from500 nm to 530 nm and a peak wavelength ranging from 570 nm to 580 nm areboth more favorable to similar degrees, and a peak wavelength rangingfrom 530 nm to 570 nm is extremely favorable.

If a light-emitting element that emits a purple light, such as a purplesemiconductor light-emitting element, is used in a specific lightemitting area, and a blue phosphor is also used in the same lightemitting area, the full-width at half-maximum of an emission spectrum ofthe phosphor material used in the intermediate wavelength range whenphotoexcited at room temperature is favorably 130 nm or less, morefavorably 110 nm or less, extremely favorably 90 nm or less, anddramatically favorably 70 nm or less. On the other hand, since anexcessively narrow band spectrum may result in a case where desiredcharacteristics cannot be realized unless a large number of differenttypes of light-emitting elements are mounted in a light-emitting device,hence if a light-emitting element that emits purple light is used, thefull-width at half-maximum of the phosphor material used in theintermediate wavelength range is favorably 2 nm or more, more favorably4 nm or more, extremely favorably 6 nm or more, and dramaticallyfavorably 8 nm or more.

On the other hand, if a light-emitting element that emits a blue light,such as a blue semiconductor light-emitting element, is used in aspecific light emitting area, for example, it is preferable thatphosphor, which emits light in the intermediate wavelength range, emitslight in a broad band. The reason for this follows. Generally thefull-width at half-maximum of the blue semiconductor light-emittingelement is relatively narrow, therefore if the phosphor, which emitslight in the intermediate wavelength range, emits light in a narrowband, the concave portion in the spectral power distribution formed inthe range of 465 nm or more and 525 nm or less, which is critical toimplement “a natural, vivid, highly visible and comfortable appearanceof colors and appearance of objects”, becomes excessively large(relative spectral intensity becomes too low), which makes it difficultto implement the desired characteristics.

In such a case, in consideration of D_(uv) controllability, a peakwavelength of an intermediate wavelength range phosphor materialfavorably ranges from 511 nm to 543 nm. A peak wavelength ranging from514 nm to 540 nm is more favorable, a peak wavelength ranging from 520nm to 540 nm is extremely favorable, and a peak wavelength ranging from520 nm to 530 nm is dramatically favorable.

If a light-emitting element that emits a blue light, such as a bluesemiconductor light-emitting element, is used in a specific lightemitting area, the full-width at half-maximum of an emission spectrum ofthe phosphor material used in the intermediate wavelength range whenphotoexcited at room temperature is favorably 90 nm or more, morefavorably 96 nm or more, and extremely favorably 97 nm or more. Anextremely broad band spectrum may not be able to implement the desiredcharacteristics, because the concave position in the spectral powerdistribution formed in the range of 465 nm or more and 525 nm or less,which is critical to implement “a natural, vivid, highly visible andcomfortable appearance of colors and appearance of objects”, becomes toosmall (relative spectral intensity becomes too high), hence thefull-width at half-maximum of the intermediate wavelength range phosphormaterial is favorably 110 nm or less, more favorably 108 or less,extremely favorably 104 nm or less, and dramatically favorably 103 nm orless.

As for specific examples of the intermediate wavelength range phosphormaterial used in the light-emitting device according to the firstembodiment of the first invention of the present invention, and thelight-emitting device, the method for manufacturing the light-emittingdevice, the method for designing the light-emitting device or theillumination method according to the second embodiment of the first,fifth, second or fourth invention of the present invention, any phosphormaterial satisfying the full-width at half-maximum described above canbe favorably used.

For example, as the phosphor that emits light in the intermediatewavelength range when a light-emitting element that emits a purpleslight, such as a purple semiconductor light-emitting element, is used ina specific light emitting area, and a blue phosphor is also used in thesame light emitting area, a green phosphor that includes Eu²⁺, Ce³⁺ orthe like as the activator, can be used. A preferable green phosphorusing Eu²⁺ as an activator is a green phosphor which uses a crystalconstituted by alkaline-earth silicate, alkaline-earth nitride silicate,or SiAlON as a host. A green phosphor of this type can normally beexcited using a semiconductor light-emitting element ranging fromultraviolet to blue.

Specific examples of those using an alkaline-earth silicate crystal as ahost include a phosphor represented by the following general formula (6)and a phosphor represented by the following general formula (6)′.Ba_(a)Ca_(b)Sr_(c)Mg_(d)Eu_(x)SiO₄  (6)(In the general Formula (6), a, b, c, d, and x satisfy a+b+c+d+x=2,1.0≦a≦2.0, 0≦b<0.2, 0.2≦c≦1.0, 0≦d<0.2, and 0<x≦0.5.) (Alkaline-earthsilicate represented by the general formula (6) is referred to as a BSSphosphor).Ba_(1−x−y)Sr_(x)Eu_(y)Mg_(1−z)Mn_(z)Al₁₀O₁₇  (6)′(In the general formula (6)′, x, y, and z respectively satisfy0.1≦x≦0.4, 0.25≦y≦0.6, and 0.05≦z≦0.5). (An alkaline-earth aluminatephosphor represented by general formula (6)′ is referred to as a G-BAMphosphor).

Specific examples having a SiAlON crystal as a host include a phosphorrepresented by Si_(6−z)Al_(z)O_(z)N_(8−z):Eu (where 0<z<4.2) (thisphosphor is referred to as a β-SiAlON phosphor). Preferable greenphosphors using Ce³⁺ as an activator include a green phosphor with agarnet-type oxide crystal as a host such as Ca₃(Sc, Mg)₂Si₃O₁₂:Ce or agreen phosphor with an alkaline-earth scandate crystal as a host such asCaSc₂O₄:Ce. Other examples include SrGaS₄:Eu²⁺.

Still other examples include an oxynitride phosphor represented by (Ba,Ca, Sr, Mg, Zn, Eu)₃Si₆O₁₂N₂ (this phosphor is referred to as a BSONphosphor).

Yet other examples include a yttrium aluminum garnet phosphorrepresented by (Y_(1−u)Gd_(u))₃(Al_(1−v)Ga_(v))₅O₁₂:Ce, Eu (where u andv respectively satisfy 0≦u≦0.3 and 0≦v≦0.5) (this phosphor is referredto as a YAG phosphor) and a lanthanum silicon nitride phosphorrepresented by Ca_(1.5x)La_(3−x)Si₆N₁₁:Ce (where x satisfies 0≦x≦1)(this phosphor is referred to as an LSN phosphor.)

Among the phosphors described above, favorable examples include a BSSphosphor, a β-SiAlON phosphor, a BSON phosphor, a G-BAM phosphor, a YAGphosphor, and a SrGaS₄:Eu²⁺ phosphor.

On the other hand, as a phosphor that emits light in the intermediatewavelength range when a light-emitting element that emits a blue light,such as a blue semiconductor light-emitting element, is used in aspecific light emitting area, a green phosphor, of which host is Ce³⁺activated aluminate, Ce³⁺ activated yttrium-aluminum oxide, Eu²⁺activated alkaline earth silicate crystals or Eu²⁺ activated alkalineearth-silicon nitride, can be used. These green phosphors can normallybe excited using a semiconductor light-emitting element ranging fromultraviolet to blue.

Specific examples of the Ce³⁺ activated aluminate phosphor include agreen phosphor represented by the following general formula (8),Y_(a)(Ce,Tb,Lu)_(b)(G_(a),S_(c))_(c)Al_(d)O_(e)  (8)(In the general formula (8), a, b, c, d and e satisfy a+b=3, 0≦b≦0.2,4.5≦c+d≦5.5, 0.1≦c≦2.6, and 10.8≦e≦13.4.) (Ce³⁺ activated aluminatephosphor represented by the general formula (8) is referred to as aG-YAG phosphor).

In the G-YAG phosphor in particular, the composition range thatsatisfies the general formula (8) can be suitably selected. In thisembodiment, the wavelength and the full-width at half-maximum thatimplement the maximum emission intensity when light is excited with thephosphor alone are preferably in the following ranges.

0.01≦b≦0.05 and 0.1≦c≦2.6 is preferable,

0.01≦b≦0.05 and 0.3≦c≦2.6 is more preferable, and

0.01≦b≦0.05 and 1.0≦c≦2.6 is extremely preferable;

0.01≦b≦0.03 and 0.1≦c≦2.6 is also preferable,

0.01≦b≦0.03 and 0.3≦c≦2.6 is more preferable, and

0.01≦b≦0.03 and 1.0≦c≦2.6 is extremely preferable.

Specific examples of Ce³⁺ activated yttrium-aluminum oxide phosphorinclude a green phosphor represented by the following general formula(9).Lu_(a)(Ce,Tb,Lu)_(b)(G_(a),S_(c))_(c)Al_(d)O_(e)  (9)(In the general formula (9), a, b, c, d and e satisfy a+b=3, 0≦b≦0.2,4.5≦c+d≦5.5, 0≦c≦2.6, and 10.8≦e≦13.4.) (the Ce³⁺ activatedyttrium-aluminum oxide phosphor represented by the general formula (9)is called “LuAG phosphor”.)

In the LuAG phosphor, in particular, the composition range thatsatisfies the general formula (9) can be suitably selected. In thisembodiment, the wavelength and the full-width at half-maximum thatimplement the maximum emission intensity when light is excited with thephosphor alone are preferably in the following ranges.

0.00≦b≦0.13 is preferable,

0.02≦b≦0.13 is more preferable, and

0.02≦b≦0.10 is extremely preferable.

Other examples include green phosphors represented by the followinggeneral formula (10) and a phosphor represented by the following generalformula (11).M¹ _(a)M² _(b)M³ _(c)O_(d)  (10)(In the general formula (10), M¹ indicates a bivalent metallic element,M² indicates a trivalent metallic element, and M³ indicates atetravalent metallic element, and a, b, c and d satisfy 2.7≦a≦3.3,1.8≦b≦2.2, 2.7≦c≦3.3 and 11.0≦d≦13.0.)(the phosphor represented by the general formula (10) is referred to asa CSMS phosphor).

In the above general formula (10), M¹ is a bivalent metallic element,and is preferably at least one type selected from the group consistingof Mg, Ca, Zn, Sr, Cd and Ba, further preferably Mg, Ca or Zn, andparticularly preferably Ca. In this case, Ca may be a single system ormay be a composite system with Mg. M¹ may include other bivalentmetallic elements.

M² is a trivalent metallic element, and is preferably at least one typeselected from the group consisting of Al, Sc, Ga, Y, In, La, Gd and Lu,further preferably Al, Sc, Y or Lu, and particularly preferably Sc. Inthis case, Sc may be a single system or may be a composite system with Yor Lu. M² must include Ce and may include other trivalent metallicelements.

M³ is a tetravalent metallic element, and preferably includes at leastSi. An example of a tetravalent metallic element M³, other than Si, ispreferably at least one type selected from the group consisting of Ti,Ge, Zr, Sn and Hf, further preferably at least one type selected fromthe group consisting of Ti, Zr, Sn and Hf, and particularly preferablySn. Particularly it is preferable that M³ is Si. M³ may include othertetravalent metallic elements.

In the CSMS phosphor in particular, the composition range that satisfiesthe general formula (10) can be suitably selected. For the wavelengthand the full-width at half-maximum that implement the maximum emissionintensity when light is excited with the phosphor alone to be in apreferable range in this embodiment, the lower limit of the ratio of Ceincluded in M² to the entire M² is preferably 0.01 or more, and morepreferably 0.02 or more. Further, the upper limit of the ratio of Ceincluded in M² to the entire M² is preferably 0.10 or less, and morepreferably 0.06 or less. Further, the lower limit of the ratio of Mgincluded in M¹ to the entire M¹ is preferably 0.01 or more, and morepreferably 0.03 or more. On the other hand, the upper limit ispreferably 0.30 or less, and more preferably 0.10 or less.

Furthermore, examples include represented by the following generalformula (11).M¹ _(a)M² _(b)M³ _(c)O_(d)  (11)(In the general formula (11), M¹ indicates an activator elementincluding at least Ce, M² is a bivalent metallic element, and M³ is atrivalent metallic element, and a, b, c and d satisfy 0.0001≦a≦0.2,0.8≦b≦1.2, 1.6≦c≦2.4 and 3.2≦d≦4.8.) (A phosphor represented by thegeneral formula (11) is called “CSO phosphor”.)

In the above general formula (11), M¹ is an activator element containedin a host crystal, and includes at least Ce. M¹ can contain at least onetype of bivalent to tetravalent element selected from the groupconsisting of Cr, Mn, Fe, Co, Ni, Cu, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho,Er, Tm and Yb.

M² is a bivalent metallic element, and is preferably at least one typeselected from the group consisting of Mg, Ca, Zn, Sr, Cd and Ba, furtherpreferably Mg, Ca or Sr, and is particularly preferably that Ca is 50mol % or more of the elements of M².

M³ is a trivalent metallic element, and is preferably at least one typeselected from the group consisting of Al, Sc, Ga, Y, In, La, Gd, Yb andLu, and further preferably Al, Sc, Yb or Lu, more further preferably Sc,or Sc and Al, or Sc and Lu, and is particularly preferably that Sc is 50mol % or more of the elements of M³.

M² and M³ are a bivalent metallic element and trivalent metallic elementrespectively, and a small part of M² and/or M³ may be a metallic elementof which valence is any one of 1, 4 and 5, and a very small amount ofanions, such as a halogen element (F, Cl, Br, I), nitrogen, sulfurselenium or the like may be contained in the compound.

In a CSO phosphor in particular, a composition range that satisfies thegeneral formula (11) can be suitably selected. In this embodiment, thewavelength and the full-width at half-maximum that implement the maximumemission intensity when light is excited with phosphor alone arepreferably in the following ranges.

0.005≦a≦0.200 is preferable,

0.005≦a≦0.012 is more preferable, and

0.007≦a≦0.012 is extremely preferable.

Furthermore, specific examples of green phosphors using analkaline-earth silicate crystal as a host and Eu²⁺ as an activatorinclude a phosphor represented by the following general formula (12).Ba_(a)Ca_(b)Sr_(c)Mg_(d)Eu_(x)SiO₄  (12)(In the general Formula (12), a, b, c, d, and x satisfy a+b+c+d+x=2,1.0≦a≦2.0, 0≦b<0.2, 0.2≦c≦1.0, 0≦d<0.2, and 0<x≦0.5.) (Alkaline-earthsilicate represented by the general formula (12) is referred to as a BSSphosphor).

In the BSS phosphor, a composition range that satisfies the generalformula (12) can be suitable selected. In this embodiment, thewavelength and the full-width at half-maximum that implement the maximumemission intensity when light is excited with the phosphor alone arepreferably in the following ranges.

0.20≦c≦1.00 and 0.25<x≦0.50 is more preferable.

0.20≦c≦1.00 and 0.25<x≦0.30 is extremely preferable;

Furthermore, 0.50≦c≦1.00 and 0.00<x≦0.50 is preferable,

0.50≦c≦1.00 and 0.25<x≦0.50 is more preferable, and

0.50≦c≦1.00 and 0.25<x≦0.30 is extremely preferable.

Furthermore, specific examples of phosphors using an alkaline-earthnitride silicate crystal as a host and Eu²⁺ as an activator include aphosphor represented by the following general formula (13).

(Ba, Ca, Sr, Mg, Zn, Eu)₃Si₆O₁₂N₂ (13) (Alkaline-earth nitride silicaterepresented by the general formula (13) is referred to as a BSONphosphor).

In the BSON phosphor, a composition range that satisfies the generalformula (13) can be suitable selected. In this example, the wavelengthand the full-width at half-maximum that implement the maximum emissionintensity when light is excited with the phosphor alone are preferablyin the following ranges.

In the general formula (13), a combination of Ba, Sr and Eu ispreferably among the selectable bivalent metallic elements (Ba, Ca, Sr,Mg, Zn, Eu), and the ratio of Sr to Ba is preferably 10 to 30%.

Next, in the long wavelength range from Λ3 (590 nm) to 780 nm among thethree wavelength ranges, light emitted from all light sources can beincluded, such as thermal emission light from a hot filament or thelike, electric discharge emission light from a fluorescent tube, ahigh-pressure sodium lamp, or the like, stimulated emission light from alaser or the like, spontaneous emission light from a semiconductorlight-emitting element, and spontaneous emission light from a phosphor.Among the above, emission of light from a photoexcited phosphor,emission of light from a photoexcited semiconductor light-emittingelement, and emission of light from a photoexcited semiconductor laserare favorable due to their small sizes, high energy efficiency, andtheir ability to emit light in a relatively narrow band.

Specifically, the following is favorable.

As the semiconductor light-emitting element, an orange light-emittingelement (with a peak wavelength of around 590 nm to 600 nm) or a redlight-emitting element (from 600 nm to 780 nm) in which an AlGaAsmaterial formed on a GaAs substrate or an (Al)InGaP material formed on aGaAs substrate is included in an active layer structure is favorable. Inaddition, a red light-emitting element (from 600 nm to 780 nm) in whichan GaAsP material formed on a GaP substrate is included in an activelayer structure is favorable.

The active layer structure may be any of a multiple quantum wellstructure in which a quantum well layer and a barrier layer arelaminated, a single or a double heterostructure including a relativelythick active layer and a barrier layer (or a clad layer), and a homojunction constituted by a single pn junction.

In particular, in this wavelength range, a peak wavelength is favorablyclose to a vicinity of 630 nm in consideration of achieving a balancebetween D_(uv) controllability and luminous efficacy of radiation. Fromthis perspective, a red light-emitting element is more favorable than anorange light-emitting element. In other words, a semiconductorlight-emitting element having an emission peak in the long wavelengthrange from Λ3 (590 nm) to 780 nm in the first to fifth inventions of thepresent invention is favorably an orange light-emitting element (with apeak wavelength of around 590 nm to 600 nm), more favorably a redlight-emitting element (with a peak wavelength of around 600 nm to 780nm), and extremely favorably a red light-emitting element with a peakwavelength that is close to around 630 nm. In particular, a redlight-emitting element with a peak wavelength ranging from 615 nm to 645nm is extremely favorable.

In addition, a semiconductor laser is also favorably used as alight-emitting element. For the same reasons as described above, anemission wavelength is favorably within an orange range (with a peakwavelength of around 590 nm to 600 nm), more favorably within a redrange (with a peak wavelength of around 600 nm to 780 nm), and extremelyfavorably within a red range in which a peak wavelength is close toaround 630 nm. In particular, a red semiconductor laser with a peakwavelength ranging from 615 nm to 645 nm is extremely favorable.

With a long wavelength range semiconductor light-emitting element thatis used in the light-emitting device according to the first embodimentof the first invention of the present invention, and the light-emittingdevice, the method for manufacturing the light-emitting device, themethod for designing the light-emitting device or the illuminationmethod according to the second embodiment of the first, fifth, second orfourth invention of the present invention, a full-width at half-maximumof an emission spectrum of the semiconductor light-emitting element isfavorably narrow. From this perspective, the full-width at half-maximumof the semiconductor light-emitting element used in the long wavelengthrange is favorably 30 nm or less, more favorably 25 nm or less,extremely favorably 20 nm or less, and dramatically favorably 15 nm orless. On the other hand, since an excessively narrow band spectrum mayresult in a case where desired characteristics cannot be realized unlessa large number of different types of light-emitting elements are mountedin a light-emitting device, the full-width at half-maximum of thesemiconductor light-emitting element used in the long wavelength rangeis favorably 2 nm or more, more favorably 4 nm or more, extremelyfavorably 6 nm or more, and dramatically favorably 8 nm or more.

In the long wavelength range, light in the emission wavelength range isabsorbed due to a bandgap of the GaAs substrate being smaller than abandgap of the material constituting the active layer structure.Therefore, as far as substrate thickness is concerned, the substrate isfavorably thin or completely removed.

With a long wavelength range phosphor material that is used in thelight-emitting device according to the first embodiment of the firstinvention of the present invention, and the light-emitting device, themethod for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention, a full-width at half-maximum of the phosphormaterial is favorably narrow. From this perspective, the full-width athalf-maximum of an emission spectrum of the phosphor material used inthe long wavelength range when photoexcited at room temperature isfavorably 130 nm or less, more favorably 110 nm or less, extremelyfavorably 90 nm or less, and dramatically favorably 70 nm or less. Onthe other hand, since an excessively narrow band spectrum may result ina case where desired characteristics cannot be realized unless a largenumber of different types of light-emitting elements are mounted in alight-emitting device, the full-width at half-maximum of the phosphormaterial used in the long wavelength range is favorably 2 nm or more,more favorably 4 nm or more, extremely favorably 6 nm or more, anddramatically favorably 8 nm or more.

With a long wavelength range phosphor material, when creating alight-emitting device by integrating the phosphor material with othermaterials, a peak wavelength is extremely favorably close to 630 nm inconsideration of achieving a balance between D_(uv) controllability andluminous efficacy of radiation. In other words, a phosphor materialhaving an emission peak in a long wavelength range from Λ3 (590 nm) to780 nm in the first to fifth inventions of the present invention has apeak that is favorably between 590 nm and 600 nm and more favorablyaround 600 nm to 780 nm, and a peak wavelength is extremely favorablyclose to 630 nm. In particular, a phosphor material with a peakwavelength ranging from 620 nm to 655 nm is extremely favorable.

As for specific examples of the long wavelength range phosphor materialused in the light-emitting device according to the first embodiment ofthe first invention of the present invention, and the light-emittingdevice, the method for manufacturing the light-emitting device, themethod for designing the light-emitting device or the illuminationmethod according to the second embodiment of the first, fifth, second orfourth invention of the present invention, any phosphor materialsatisfying the full-width at half-maximum described above can befavorably used. In addition, such specific examples include phosphorsusing Eu²⁺ as an activator and a crystal constituted by alkaline-earthsilicon-nitride, a SiAlON, or alkaline-earth silicate as a host. A redphosphor of this type can normally be excited using a semiconductorlight-emitting element ranging from ultraviolet to blue. Specificexamples of phosphors using an alkaline-earth silicon-nitride crystal asa host include a phosphor represented by (Ca, Sr, Ba, Mg)AlSiN₃:Euand/or (Ca, Sr, Ba)AlSiN₃:Eu (this phosphor is referred to as a SCASNphosphor), a phosphor represented by (CaAlSiN₃)_(1−x)(Si₂N₂O)_(x):Eu(where x satisfies 0<x<0.5) (this phosphor is referred to as a CASONphosphor), a phosphor represented by (Sr, Ca,Ba)₂Al_(x)Si_(5−x)O_(x)N_(8−x):Eu (where 0≦x≦2), and a phosphorrepresented by Eu_(y)(Sr, Ca, Ba)_(1−y):Al_(1+x)Si_(4−x)O_(x)N_(7−x)(where 0≦x<4, 0≦y<0.2).

Other examples include a Mn⁴⁺-activated fluoride complex phosphor. AMn⁴⁺-activated fluoride complex phosphor is a phosphor which uses Mn⁴⁺as an activator and a fluoride complex salt of an alkali metal, amine,or an alkaline-earth metal as a host crystal. Fluoride complex saltswhich form the host crystal include those whose coordination center is atrivalent metal (B, Al, Ga, In, Y, Sc, or a lanthanoid), a tetravalentmetal (Si, Ge, Sn, Ti, Zr, Re, or Hf), and a pentavalent metal (V, P,Nb, or Ta), and the number of fluorine atoms coordinated around thecenter ranges from 5 to 7.

A favorable Mn⁴⁺-activated fluoride complex phosphor isA_(2+x)M_(y)Mn_(z)F_(n) (where A is Na and/or K; M is Si and Al; and−1≦x≦1 and 0.9≦y+z≦1.1 and 0.001≦z≦0.4 and 5≦n≦7) which uses ahexafluoro complex of an alkali metal as a host crystal. Among theabove, particularly favorable are phosphors in which A is one or moretypes selected from K (potassium) or Na (sodium) and M is Si (silicon)or Ti (titanium), such as K₂SiF₆:Mn (this phosphor is referred to as aKSF phosphor) or K₂Si_(1−x)Na_(x)Al_(x)F₆:Mn, K₂TiF₆:Mn (this phosphoris referred to as a KSNAF phosphor) that is obtained by replacing a part(favorably, 10 mol % or less) of the components of K₂SiF₆:Mn with Al andNa.

Other examples include a phosphor represented by the following generalformula (7) and a phosphor represented by the following general formula(7)′.(La_(1−x−y)Eu_(x)Ln_(y))₂O₂S  (7)(In the general formula (7), x and y denote numbers respectivelysatisfying 0.02≦x≦0.50 and 0≦y≦0.50, and Ln denotes at least onetrivalent rare-earth element among Y, Gd, Lu, Sc, Sm, and Er). (Alanthanum oxysulfide phosphor represented by the general formula (7) isreferred to as an LOS phosphor).(k−x)MgO.xAF₂.GeO₂ :yMn⁴⁺  (7)′(In the general formula (7)′, k, x, and y denote numbers respectivelysatisfying 2.8≦k≦5, 0.1≦x≦0.7, and 0.005≦y≦0.015, and A is any ofcalcium (Ca), strontium (Sr), barium (Ba), zinc (Zn), and a mixtureconsisted of these elements). (A germanate phosphor represented by thegeneral formula (7) is referred to as an MGOF phosphor).

Among the phosphors described above, favorable examples include a LOSphosphor, an MGOF phosphor, a KSF phosphor, a KSNAF phosphor, a SCASNphosphor, a CASON phosphor, a (Sr, Ca, Ba)₂Si₅N₈:Eu phosphor and a (Sr,Ca, Ba)AlSi₄N₇ phosphor.

In the light-emitting device according to the first embodiment of thefirst invention of the present invention, and the light-emitting device,the method for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention, no particular restrictions are applied tomaterials for appropriately controlling a spectral power distribution ofthe light-emitting device. However, it is extremely favorable to realizea light-emitting device such as those described below.

For example, if a light-emitting element that emits a purple light, suchas a purple semiconductor light-emitting element, is used in a specificlight emitting area, and a blue phosphor is also used in the same lightemitting area, the light-emitting device includes the phosphor whichemits light in the intermediate wavelength range in the following cases.

It is favorable to use a purple LED (with a peak wavelength of around395 nm to 420 nm) as a short wavelength range light-emitting element,and further incorporate at least one or more phosphors selected from agroup of relatively narrow band phosphors consisting of SBCA, SCA, andBAM in a light source as a light-emitting element in the shortwavelength range, incorporate at least one or more phosphors selectedfrom a group of relatively narrow band phosphors consisting of β-SiAlON,BSS, BSON, and G-BAM in the light source as a light-emitting element inthe intermediate wavelength range, and incorporate at least one or morephosphors selected from the group consisting of CASON, SCASN, LOS, KSF,and KSNAF in the light source as a light-emitting element in the longwavelength range.

A further description is given below.

It is extremely favorable to use a purple LED (with a peak wavelength ofaround 395 nm to 420 nm) as a first light-emitting element in the shortwavelength range, further incorporate SBCA that is a relatively narrowband phosphor in a light source as a second light-emitting element inthe short wavelength range, use β-SiAlON that is a relatively narrowband phosphor as a first light-emitting element in the intermediatewavelength range, and use CASON as a first light-emitting element in thelong wavelength range.

In addition, it is extremely favorable to use a purple LED (with a peakwavelength of around 395 nm to 420 nm) as a first light-emitting elementin the short wavelength range, further incorporate SCA that is arelatively narrow band phosphor in a light source as a secondlight-emitting element in the short wavelength range, include β-SiAlONthat is a relatively narrow band phosphor as a first light-emittingelement in the intermediate wavelength range, and use CASON as a firstlight-emitting element in the long wavelength range.

Furthermore, it is extremely favorable to use a purple LED (with a peakwavelength of around 395 nm to 420 nm) as a first light-emitting elementin the short wavelength range, further incorporate BAM that is arelatively narrow band phosphor in a light source as a secondlight-emitting element in the short wavelength range, use BSS that is arelatively narrow band phosphor as a first light-emitting element in theintermediate wavelength range, and use CASON as a first light-emittingelement in the long wavelength range.

Meanwhile, it is favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a short wavelength rangelight-emitting element, incorporate at least one or more phosphorsselected from a group of relatively narrow band phosphors consisting ofβ-SiAlON, BSS, BSON, and G-BAM in a light source as a light-emittingelement in the intermediate wavelength range, and incorporate at leastone or more phosphors selected from the group consisting of CASON,SCASN, LOS, KSF, and KSNAF in the light source as a light-emittingelement in the long wavelength range.

A further description is given below.

It is extremely favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a light-emitting element inthe short wavelength range, further use BSON that is a relatively narrowband phosphor as a first light-emitting element in the intermediatewavelength range, and use SCASN as a first light-emitting element in thelong wavelength range.

It is extremely favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a light-emitting element inthe short wavelength range, further use β-SiAlON that is a relativelynarrow band phosphor as a first light-emitting element in theintermediate wavelength range, and use CASON as a first light-emittingelement in the long wavelength range.

It is extremely favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a light-emitting element inthe short wavelength range, further use β-SiAlON that is a relativelynarrow band phosphor as a first light-emitting element in theintermediate wavelength range, use CASON as a first light-emittingelement in the long wavelength range, and use KSF or KSNAF as a secondlight-emitting element in the long wavelength range.

It is extremely favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a light-emitting element inthe short wavelength range, further use β-SiAlON that is a relativelynarrow band phosphor as a first light-emitting element in theintermediate wavelength range, and use SCASN as a first light-emittingelement in the long wavelength range.

It is extremely favorable to use a bluish purple LED (with a peakwavelength of around 420 nm to 455 nm) and/or a blue LED (with a peakwavelength of around 455 nm to 485 nm) as a light-emitting element inthe short wavelength range, further use β-SiAlON that is a relativelynarrow band phosphor as a first light-emitting element in theintermediate wavelength range, use SCASN as a first light-emittingelement in the long wavelength range, and use KSF or KSNAF as a secondlight-emitting element in the long wavelength range.

With the combinations of light-emitting elements described above, peakwavelength positions, full-widths at half-maximum, and the like of therespective light-emitting elements are extremely advantageous inrealizing a color appearance or an object appearance perceived asfavorable by the subjects in the visual experiments.

If a light-emitting element that emits a blue light, such as a bluesemiconductor light-emitting element, is used in a specific lightemitting area, the following combinations of the light-emitting elementsare preferable.

It is preferable that a blue light-emitting element is included in thespecific light emitting area, at least one green phosphor selected fromCa₃ (Sc, Mg)₂Si₃O₁₂:Ce (CSMS phosphor), CaSc₂O₄:Ce (CSO phosphor), andLu₃Al₅O₁₂:Ce (LuAG phosphor), Y₃(Al, Ga)₅O₁₂:Ce (G-YAG phosphor) isincluded as the phosphor in the intermediate wavelength range, and atleast one red phosphor selected from (Sr, Ca) AlSiN₃:Eu (SCASNphosphor), CaAlSi(ON)₃:Eu (CASON phosphor) and CaAlSiN₃:Eu (CASNphosphor) is also included, and it is preferable that the light-emittingdevice includes this light emitting area.

In the light-emitting device according to the first embodiment of thefirst invention of the present invention, and the light-emitting device,the method for manufacturing the light-emitting device, the method fordesigning the light-emitting device or the illumination method accordingto the second embodiment of the first, fifth, second or fourth inventionof the present invention, it is favorable to use the light-emittingelements (light-emitting materials) heretofore described because theindex A_(cg), the luminous efficacy of radiation K (lm/W), D_(uv), andthe like can be more readily set to desired values. Using thelight-emitting elements described above is also favorable because|Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| which are related,when light is treated as a color stimulus, to a difference between colorappearances of the 15 color samples when illumination by thelight-emitting device is assumed and color appearances when illuminationby calculational reference light is assumed can also be more readily setto desired values.

Various means are conceivable for lowering D_(uv) from zero to setD_(uv) to an appropriate negative value. For example, when alight-emitting device having one light-emitting element in each of thethree wavelength ranges is assumed, an emission position of thelight-emitting element in the short wavelength range can be moved towarda shorter wavelength side, an emission position of the light-emittingelement in the long wavelength range can be moved toward a longerwavelength side, an emission position of the light-emitting element inthe intermediate wavelength range can be displaced from 555 nm.Furthermore, a relative emission intensity of the light-emitting elementin the short wavelength range can be increased, a relative emissionintensity of the light-emitting element in the long wavelength range canbe increased, a relative emission intensity of the light-emittingelement in the intermediate wavelength range can be decreased, or thelike. In doing so, in order to vary D_(uv) without varying the CCT, theemission position of the light-emitting element in the short wavelengthrange may be moved toward a shorter wavelength side and, at the sametime, the emission position of the light-emitting element in the longwavelength range may be moved toward a longer wavelength side, or thelike. Moreover, operations opposite to those described above may beperformed to vary D_(uv) toward a positive side.

In addition, when a light-emitting device respectively having twolight-emitting elements in each of the three wavelength ranges isassumed, D_(uv) can be lowered by, for example, increasing a relativeintensity of a light-emitting element on a relatively shorter wavelengthside among the two light-emitting elements in the short wavelengthrange, increasing a relative intensity of a light-emitting element on arelatively longer wavelength side among the two light-emitting elementsin the long wavelength range, or the like. In doing so, in order to varyD_(uv) without varying the CCT, the relative intensity of thelight-emitting element on a relatively shorter wavelength side among thetwo light-emitting elements in the short wavelength range is increasedand, at the same time, the relative intensity of the light-emittingelement on a relatively longer wavelength side among the twolight-emitting elements in the long wavelength range is increased.Moreover, operations opposite to those described above may be performedto vary D_(uv) toward a positive side.

Meanwhile, as means for varying |Δh_(n)|, SAT_(av), ΔC_(n), and|ΔC_(max)−ΔC_(min)| which are related to a difference between colorappearances of the 15 color samples when illumination by thelight-emitting device is assumed and color appearances when illuminationby calculational reference light is assumed and, in particular, as meansfor increasing ΔC_(n), operations such as described below can beperformed after adjusting an entire spectral power distribution so thatD_(uv) assumes a desired value. Operations which may be performedinclude replacing each light-emitting element with a material having anarrow full-width at half-maximum, forming a spectrum shape in whichlight-emitting elements are appropriately separated from each other,installing a filter that absorbs a desired wavelength in an illuminationlight source, a lighting fixture, or the like in order to form a concaveand/or a convex shape in a spectrum of each light-emitting element, andadditionally mounting a light-emitting element which performs emissionat a narrower band in a light-emitting element.

As described above, the first to fifth inventions of the presentinvention reveals a primary illumination method or a primarylight-emitting device for producing, with respect to a wide variety ofilluminated objects with various hues, a color appearance or an objectappearance which is as natural, vivid, highly visible, and comfortableas though perceived in a high-illuminance environment such as outdoorswhere illuminance exceeds 10000 lx, within an illuminance range ofapproximately 150 lx to approximately 5000 lx for which visualexperiments have been carried out. In particular, the first to fifthinventions of the present invention provides respective hues withnatural vividness and, at the same time, enables white objects to beperceived more whiter as compared to experimental reference light.

Means according to the embodiment of the first to fifth inventions ofthe present invention for producing a color appearance or an objectappearance which is as natural, vivid, highly visible, and comfortableas perceived in a high-illuminance environment involve providing alight-emitting device setting D_(uv) of light at a position of anilluminated object to within an appropriate range and, at the same time,setting indices related to a difference between color appearances of the15 color samples when illumination by the light is assumed and colorappearances when illumination by calculational reference light isassumed such as |Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| towithin appropriate ranges.

a light-emitting device used in the illumination method according to thefourth invention of the present invention can be configured in anyway aslong as the device is capable of providing such illumination. Forexample, the device may be any of an individual illumination lightsource, an illuminating module in which at least one or more of thelight sources is mounted on a heatsink or the like, and a lightingfixture in which a lens, a light-reflecting mechanism, a drivingelectric circuit, and the like are added to the light source or themodule. Furthermore, the device may be a lighting system which is acollection of individual light sources, individual modules, individualfixtures, and the like and which at least has a mechanism for supportingsuch components.

In addition, the light-emitting device according to the first embodimentof the first invention of the present invention is a light-emittingdevice in which means for producing a color appearance or an objectappearance which is as natural, vivid, highly visible, and comfortableas perceived in a high-illuminance environment involve setting D_(uv) asobtained from a spectral power distribution of light emitted in a mainradiant direction to within an appropriate range and, at the same time,setting the index A_(cg) to within an appropriate range. For example,the device may be any of an individual illumination light source, anilluminating module in which at least one or more of the light sourcesis mounted on a heatsink or the like, and a lighting fixture in which alens, a light-reflecting mechanism, a driving electric circuit, and thelike are added to the light source or the module. Furthermore, thedevice may be a lighting system which is a collection of individuallight sources, individual modules, individual fixtures, and the like andwhich at least has a mechanism for supporting such components.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, the control element is a passiveelement that itself has no amplifying function, and is not especiallylimited if the intensity modulation for each wavelength can be performedin an appropriate range on light that is emitted from a light-emittingelement or a light-emitting device having relatively low levelprocessing, in the main radiant direction, and can constitute alight-emitting device having high level processing. In the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention, this function may be expressed as an action of thecontrol element on a light-emitting element. Examples of the controlelement according to the second embodiment of the first, second, fourthand fifth inventions of the present invention are passive devices, suchas a reflection mirror, an optical filter and various types of opticallenses. The control element according to the second embodiment of thefirst, second, fourth and fifth inventions of the present invention maybe an absorption material that is dispersed in the sealing material ofthe packaged LED, so as to perform intensity modulation for eachwavelength in an appropriate range. However, a light-emitting elementand a reflection mirror, an optical filter, an absorption material orthe like that can perform intensity modulation, of which wavelengthdependency is low, on the light emitted from a light-emitting devicehaving relatively low level processing, are not included in the controlelement.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, the control element is forconverting the spectral power distribution of the light emitted from thelight-emitting element in the primary radiation direction into aspectral power distribution of the light that satisfies both Condition 1and Condition 2 described above. Therefore the characteristics of thecontrol element according to the second embodiment of the first, second,fourth and fifth inventions of the present invention depend on thespectral power distribution of the light emitted from the light-emittingelement in the main radiant direction.

However, in some cases, certain characteristics of the light-emittingelement are preferable to make a good appearance of colors of the lightemitted from the light-emitting device to an even better appearance ofcolors.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that when D_(uv)(Φ_(elm)) denotes D_(uv) derived from the spectral power distribution ofthe light emitted from the light-emitting element in the main radiantdirection, and D_(uv) (φ_(SSL)) denotes D_(uv) derived from the spectralpower distribution of the light emitted from the light-emitting devicein the main radiant direction, the control element satisfies D_(uv)(φ_(SSL))<D_(uv) (Φ_(elm)).

The above mentioned Condition 1 specifies that −0.0350≦D_(uv)≦−0.0040 issatisfied. D_(uv) in this range is a very small value compared with acommon LED illumination which is already on the market. Therefore it ispreferable that the control element according to the second embodimentof the first, second, fourth and fifth inventions of the presentinvention has a characteristic to decrease D_(uv) of the spectral powerdistribution. However even if the control element according to thesecond embodiment of the first, second, fourth and fifth inventions ofthe present invention increase D_(uv), this is acceptable for certain ifthe light-emitting device satisfies Condition 1. For example, in thecase of a light-emitting element with which appearance of colors becomestoo strong (glaring), a good appearance of colors may be implemented bydisposing a control element that increases D_(uv)

There are various means of decreasing D_(uv), from zero to anappropriate negative value as described above, but these means can alsobe used to select a suitable control element according to the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention. For example, a control element, that increases therelative emission intensity of the light-emitting element in a shortwavelength region, increases the relative emission intensity of thelight-emitting element in a long wavelength region, and decreases therelative emission intensity of the light-emitting element in anintermediate wavelength range, more specifically, a control element ofwhich light transmittance is high in the short wavelength region and thelong wavelength region, and of which light transmittance is low in theintermediate wavelength range can be selected. A control element thatadds convex/concave portions to the spectral power distribution of thelight emitted from the light-emitting element in the primary direction,can also be selected. To change D_(uv) in a positive side, an operationthe opposite of the above mentioned operation can be performed.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that when A_(cg)(Φ_(elm)) denotes A_(cg) derived from the spectral power distribution ofthe light emitted from the light-emitting element in the main radiantdirection, and A_(cg) (φ_(SSL)) denotes A_(cg) derived from the spectralpower distribution of the light emitted from the light-emitting devicein the main radiant direction, the control element satisfies A_(cg)(φ_(SSL))<A_(cg) (Φ_(elm)).

The above Condition 2 specifies that −360≦A_(cg)≦−10 is satisfied.A_(cg) in this range is a very small value compared with a common LEDillumination which is already on the market. Therefore it is preferablethat the control element according to the second embodiment of thefirst, second, fourth and fifth inventions of the present invention hasa characteristic to decrease A_(cg). However even if the control elementaccording to the second embodiment of the first, second, fourth andfifth inventions of the present invention increases A_(cg), it isacceptable for certain if the light-emitting device satisfies Condition2. For example, in the case of a light-emitting element with whichappearance of colors becomes too strong (glaring), a good appearance ofcolors may be implemented by disposing a control element that increasesA_(cg).

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that when SAT_(av)(Φ_(elm)) denotes an average of the saturation difference derived fromthe spectral power distribution of the light emitted from thelight-emitting element in the main radiant direction, and SAT_(av)(φ_(SSL)) denotes an average of the saturation difference derived fromthe spectral power distribution of the light emitted from thelight-emitting device in the primary radiation direction, the controlelement satisfies SAT_(av) (Φ_(elm))<SAT_(av) (φ_(SSL)).

If the average SAT_(av) of the saturation difference increases within anappropriate range, appearance of colors becomes better, hence it ispreferable that the control element according to the second embodimentof the first, second, fourth and fifth inventions of the presentinvention has a characteristic to increase SAT_(av) when theillumination by the spectral power distribution is mathematicallyassumed. However even if the control element according to the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention decreases SAT_(av), a good appearance of colors may beimplemented by disposing a control element that decreases SAT_(av) inthe case of a light-emitting element with which appearance of colorsbecomes too strong (glaring).

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that the controlelement absorbs or reflects light in the range of 380 nm≦λ(nm)≦780 nm.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that the controlelement includes a collection and/or diffusion function of light emittedfrom the light-emitting element, such as the function(s) of a concavelens, a convex lens and a Fresnel lens.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, it is preferable that the controlelement, which is often disposed close to the light-emitting element, isheat resistant. A control element that is heat resistant is, forexample, a control element made of a heat resistant material, such asglass. In the control element according to the second embodiment of thefirst, second, fourth and fifth inventions of the present invention, adesired element may be doped and colored to implement desired reflectioncharacteristics and transmission characteristics.

For the above mentioned control element according to the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention, an appropriate filter on the market that satisfiesthe requirements of the second embodiment of the first, second, fourthand fifth inventions of the present invention may be selected. A filtermay be designed and fabricated such that the light emitted from thelight-emitting device has a desired spectral power distribution.

For example, to fabricate a filter having a plurality of absorptionpeaks, a plurality of types of films having a characteristic to absorb alight in a certain wavelength region and films having a characteristicto absorb a light in other wavelength regions may be prepared, and amultilayer filter may be created by layering these films. Dielectricfilms may be stacked to create a multilayer film, so as to implementdesired characteristics.

As described above, the second embodiment of the first, second, fourthand fifth inventions of the present invention discloses a method ofimplementing a light-emitting device with controlling secondaryinfluence by light irradiation, even for illumination objects for whichthis secondary influence is of concern, while implementing a natural,vivid, highly visible and comfortable appearance of objects as if theobjects are seen, in a high luminance environment exceeding 10000 lx, asoutdoors, for various illumination objects having various hues, within a150 lx to about 5000 lx luminous range. In particular, the secondembodiment of the first, second, fourth and fifth inventions of thepresent invention provides respective hues with natural vividness and,at the same time, enables white objects to be perceived more whiter ascompared to experimental reference light.

Especially the second embodiment of the first, second, fourth and fifthinventions of the present invention is an extremely practical techniqueto provide an illumination device that implements a good appearance ofcolors by a very simple method of disposing such a control element as afilter and reflection mirror, in an illumination device which is alreadyon the market, and cannot implement a good appearance of colors.

In addition, the light-emitting device according to the secondembodiment of the first invention of the present invention is alight-emitting device in which means for producing a color appearancewhich is as natural, vivid, highly visible, and comfortable as perceivedin a high-illuminance environment involve setting D_(uv) as obtainedfrom a spectral power distribution of light emitted in a main radiantdirection to within an appropriate range and, at the same time, settingthe index A_(cg) to within an appropriate range.

In other words, according to the second embodiment of the firstinvention of the present invention, intensity modulation is performed onan appropriate wavelength in the light emitted from the light-emittingelement using a control element, and the light emitted from thelight-emitting device satisfies Conditions 1 and 2, and as long as thisrequirement is satisfied, the light-emitting device may have anyconfiguration. For example, the device may be any of an individualillumination light source, an illuminating module in which at least oneor more of the light sources is mounted on a heatsink or the like, and alighting fixture in which a lens, a light-reflecting mechanism, adriving electric circuit, and the like are added to the light source orthe module. Furthermore, the device may be a lighting system which is acollection of individual light sources, individual modules, individualfixtures, and the like and which at least has a mechanism for supportingsuch components.

Means according to the illumination method of the second embodiment ofthe fourth invention of the present invention for producing a colorappearance which is as natural, vivid, highly visible, and comfortableas perceived in a high-illuminance environment involve providing alight-emitting device setting D_(uv) of light at a position of anilluminated object to within an appropriate range and, at the same time,setting indices related to a difference between color appearances of the15 color samples when illumination by the light is assumed and colorappearances when illumination by calculational reference light isassumed such as |Δh_(n)|, SAT_(av), ΔC_(n), and |ΔC_(max)−ΔC_(min)| towithin appropriate ranges.

In other words, the illumination method according to the secondembodiment of the fourth invention of the present invention is anillumination method in which light emitted from a semiconductorlight-emitting element is included in the spectral power distribution asa constituent element and, at the same time, the illumination methodaccording to the present invention is an illumination method ofilluminating light in which |Δh_(n)|, SAT_(av), ΔC_(n),|ΔC_(max)−ΔC_(min)|, D_(uv), and the like are within appropriate rangesto an illuminated object, and a light-emitting device used in theillumination method according to the second embodiment of the fourthinvention of the present invention can be configured in any way as longas the device is capable of providing such illumination. For example,the device may be any of an individual illumination light source, anilluminating module in which at least one or more of the light sourcesis mounted on a heatsink or the like, and a lighting fixture in which alens, a light-reflecting mechanism, a driving electric circuit, and thelike are added to the light source or the module. Furthermore, thedevice may be a lighting system which is a collection of individuallight sources, individual modules, individual fixtures, and the like andwhich at least has a mechanism for supporting such components.

In the second embodiment of the first, second, fourth and fifthinventions of the present invention, the metrological, photometric andcolormetric characteristics of the light-emitting devices of theexamples are shown in Table 17 and Table 18, where appearance of colorsof the illumination objects was generally very good.

The light-emitting device according to the second embodiment of thefirst invention of the present invention is an illumination device thatcan implement a good appearance of colors for an illumination devicethat cannot implement a good appearance of colors, by using a verysimple method of disposing such a control element as a filter and areflection mirror in this illumination device, and also an illuminationdevice that can implement a good appearance of colors suitable to thetaste of the user, for an illumination device which is already capableof implementing a good appearance of colors, by using a very simplemethod of disposing such a control element as a filter and a reflectionmirror in this illumination device.

In order to achieve the objects described above, the present inventionincludes the following inventions.

[1-1]

A light-emitting device which includes M number of light-emitting areas(M is 2 or greater natural number), and incorporating a semiconductorlight-emitting element as a light-emitting element in at least one ofthe light-emitting areas, wherein

when φ_(SSL)(λ) (N is 1 to M) is a spectral power distribution of alight emitted from each light-emitting area in a main radiant directionof the light-emitting device, and φ_(SSL)(λ), which is a spectral powerdistribution of all the lights emitted from the light-emitting device inthe radiant direction, is represented by

$\begin{matrix}{\lbrack {{Expression}{\mspace{11mu}\;}52} \rbrack{{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{N(\lambda)}}}},}} & \;\end{matrix}$

the light-emitting device includes light-emitting areas so thatφ_(SSL)(λ) can satisfy the Conditions 1 to 2 by changing a luminous fluxamount and/or a radiant flux amount emitted from the light-emittingareas.

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 53]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 54]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[1-2]

The light-emitting device according to [1-1], wherein

all of φ_(SSL)N(λ) (N is 1 to M) satisfies the Condition 1 and Condition2.

[1-3]

The light-emitting device according to [1-1] or [1-2], wherein

at least one light-emitting area of the M number of light-emitting areashas wiring that allows the light-emitting area to be electrically drivenindependently from other light-emitting areas.

[1-4]

The light-emitting device according to [1-3], wherein

all the M numbers of light-emitting areas each have wiring that allowsthe light-emitting area to be electrically driven independently fromother light-emitting areas.

[1-5]

The light-emitting device according to any one of [1-1] to [1-4],wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus can be changed.

[1-6]

The light-emitting device according to [1-5], wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction can be independently controlledwhen at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[1-7]

The light-emitting device according to any one of [1-1] to [1-6],wherein

a maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light-emitting areas closest to eachother, is 0.4 mm or more and 200 mm or less.

[1-8]

The light-emitting device according to any one of [1-1] to [1-7],including the light-emitting areas that allow φ_(SSL)(λ) to furthersatisfy the following Conditions 3 to 4 by changing a luminous fluxamount and/or a radiant flux amount emitted from the light-emittingareas:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light emitted in theradiant direction are respectively denoted by a*_(nref) and b*_(nref)(where n is a natural number from 1 to 15), then each saturationdifference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 55} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 56} \rbrack & \; \\{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[1-9]

The light-emitting device according to any one of [1-1] to [1-8],wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[1-10]

The light-emitting device according to any one of [1-1] to [1-9],wherein

a correlated color temperature T_(SSL) (K) of light emitted from thelight-emitting device in the radiant direction satisfies2550(K)≦T _(SSL)(K)≦5650(K).[1-11]

A method for designing a light-emitting device which includes M numberof light-emitting areas (M is 2 or greater natural number), andincorporating a semiconductor light-emitting element as a light-emittingelement in at least one of the light-emitting areas,

the method comprising designing the light-emitting areas such that, whenφ_(SSL)(λ) (N is 1 to M) is a spectral power distribution of a lightemitted from each light-emitting area in a main radiant direction of thelight-emitting device, and φ_(SSL)(λ), which is a spectral powerdistribution of all the lights emitted from the light-emitting device inthe radiant direction, is represented by

$\begin{matrix}{\lbrack {{Expression}\mspace{14mu} 57} \rbrack{{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{N(\lambda)}}}},}} & \;\end{matrix}$

φ_(SSL)(λ) satisfies the following Conditions 1 to 2 by changing aluminous flux amount and/or a radiant flux amount emitted from thelight-emitting areas:

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) andan index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 58]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 59]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[1-12]

The method for designing a light-emitting device according to [1-11],wherein

all of φ_(SSL)N(λ) (N is 1 to M) satisfies the Condition 1 and Condition2.

[1-13]

The method for designing a light-emitting device according to [1-11] or[1-12], wherein

at least one light-emitting area of the M number of light-emitting areashas wiring that allows the light-emitting area to be electrically drivenindependently from other light-emitting areas.

[1-14]

The method for designing a light-emitting device according to [1-13],wherein

all the M numbers of light-emitting areas each have wiring that allowsthe light-emitting area to be electrically driven independently fromother light-emitting areas.

[1-15]

The method for designing a light-emitting device according to any one of[1-11] to [1-14], wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus can be changed.

[1-16]

The method for designing a light-emitting device according to [1-15],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction can be independently controlledwhen at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[1-17]

The method for designing a light-emitting device according to any one of[1-11] to [1-16], wherein

a maximum distance L between two arbitrary points on a virtual outerperiphery enveloping the entire light-emitting areas closest to eachother, is 0.4 mm or more and 200 mm or less.

[1-18]

The method for designing a light-emitting device according to any one of[1-11] to [1-17],

further comprising allowing φ_(SSL)(λ) to further satisfy the followingConditions 3 to 4 by changing a luminous flux amount and/or a radiantflux amount emitted from the light-emitting areas:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15),

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 60} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 61} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[1-19]

The method for designing a light-emitting device according to any one of[1-11] to [1-18], wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[1-20]

The method for designing a light-emitting device according to any one of[1-11] to [1-19], wherein

the correlated color temperature T_(SSL) (K) of light emitted from thelight-emitting device in the radiant direction satisfies2550(K)≦T _(SSL)(K)≦5650(K).[1-21]

A method for driving a light-emitting device which includes M number oflight-emitting areas (M is 2 or greater natural number), and has asemiconductor light-emitting element as a light-emitting element in atleast one of the light-emitting areas,

the method comprising supplying power to each light-emitting area suchthat, when φ_(SSL)(λ) (N is 1 to M) is a spectral power distribution ofa light emitted from each light-emitting area in a main radiantdirection of the light-emitting device, and φ_(SSL)(λ) which is aspectral power distribution of all the lights emitted from thelight-emitting device in the radiant direction, is represented by

[Expression  62]${{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{N(\lambda)}}}},$

φ_(SSL)(λ) satisfies the following Conditions 1 to 2:

Condition 1:

light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040,

Condition 2:

if a spectral power distribution of light emitted from thelight-emitting device in the radiant direction is denoted by φ_(SSL)(λ), a spectral power distribution of a reference light that is selectedaccording to T_(SSL) (K) of the light emitted from the light-emittingdevice in the radiant direction is denoted by φ_(ref) (λ), tristimulusvalues of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(SSL), Y_(SSL), Z_(SSL)), andtristimulus values of the reference light that is selected according toT_(SSL) (K) of the light emitted from the light-emitting device in theradiant direction are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S_(SSL) (λ) of light emittedfrom the light-emitting device in the radiant direction, a normalizedspectral power distribution S_(ref) (λ) of a reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction, and a difference ΔS (λ)between these normalized spectral power distributions are respectivelydefined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y_(ref)ΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 exists on a longer wavelength-side of λ_(R),[Expression 63]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1),and

an index A_(cg) represented by the following Formula (2) satisfies−360≦A_(cg)−10, in the case when a wavelength that produces a longestwavelength local maximum value of S_(SSL) (λ) in a wavelength range from380 nm to 780 nm is denoted by λ_(R) (nm), and a wavelength Λ4 thatassumes S_(SSL) (λ_(R))/2 does not exist on a longer wavelength-side ofλ_(R),[Expression 64]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[1-22]

The method for driving a light-emitting device according to [1-21],wherein

power is supplied to the light-emitting areas so that all of φ_(SSL)N(λ)(N is 1 to M) satisfies the Condition 1 and Condition 2.

[1-23]

The method for driving a light-emitting device according to [1-21] or[1-22], wherein

at least one light-emitting area of the M number of light-emitting areasis electrically driven independently from other light-emitting areas.

[1-24]

The method for driving a light-emitting device according to any one of[1-21] to [1-23], wherein

all the M number of light-emitting areas are electrically drivenindependently from other light-emitting areas.

[1-25]

The method for driving a light-emitting device according to any one of[1-21] to [1-24], wherein

at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.

[1-26]

The method for driving a light-emitting device according to [1-25],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is unchanged when at least oneselected from the group consisting of the index A_(cg) represented bythe Formula (1) or (2), the correlated color temperature T_(SSL)(K) andthe distance D_(uvSSL) from the black-body radiation locus is changed.

[1-27]

The method for driving a light-emitting device according to [1-25],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is decreased when the index A_(cg)represented by the Formula (1) or (2) is decreased.

[1-28]

The method for driving a light-emitting device according to [1-25],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is increased when the correlatedcolor temperature T_(SSL)(K) is increased.

[1-29]

The method for driving a light-emitting device according to [1-25],wherein

a luminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction is decreased when the distanceD_(uvSSL) from the black-body radiation locus is decreased.

[1-30]

The method for driving a light-emitting device according to any one of[1-21] to [1-29],

further comprising supplying power such that φ_(SSL)(λ) furthersatisfies the following Condition 3 and Condition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light emitted in the radiantdirection are respectively denoted by a*_(nSSL) and b*_(nSSL) (where nis a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light emitted in theradiant direction are respectively denoted by a*_(nref) and b*_(nref)(where n is a natural number from 1 to 15), then each saturationdifference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15),

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 65} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 66} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light emitted in the radiant direction are denoted by θ_(nSSL)(degrees) (where n is a natural number from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[1-31]

An illumination method comprising:

illuminated objects preparation step of preparing illuminated objects;and

an illumination step of illuminating the objects by light emitted from alight-emitting devices which includes M number of light-emitting areas(M is 2 or greater natural number), and has a semiconductorlight-emitting element as a light-emitting element in at least one ofthe light-emitting areas,

in the illumination step, when light emitted from the light-emittingdevices illuminate the objects, the objects are illuminated so that thelight measured at a position of the objects satisfies <1>, <2> and <3>below:

<1> a distance D_(uvSSL) from a black-body radiation locus as defined byANSI C78.377 of the light measured at the position of the objectssatisfies −0.0350≦D_(uvSSL)≦−0.0040;

<2> if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the light measured at theposition of the objects are respectively denoted by a*_(nSSL) andb*_(nSSL) (where n is a natural number from 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T_(SSL) (K) of the light measured at theposition of the objects are respectively denoted by a*_(nref) andb*_(nref) (where n is a natural number from 1 to 15), then eachsaturation difference ΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average saturation difference represented by formula (3) belowsatisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 67} \rbrack & \; \\\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} & (3) \\\lbrack {{Expression}\mspace{14mu} 68} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

<3> if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe light measured at the position of the objects are denoted byθ_(nSSL) (degrees) (where n is a natural number from 1 to 15), and

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light measured at the position of theobjects are denoted by θ_(nref) (degrees) (where n is a natural numberfrom 1 to 15), then an absolute value of each difference in hue angles|Δh_(n)| satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

here Δh_(n)=θ_(nSSL)−θ_(nref).

[1-32]

The illumination method according to [1-31], wherein when φ_(SSL)N(λ) (Nis 1 to M) is a spectral power distribution of a light which has beenemitted from each light-emitting element and has reached the position ofthe objects, and φ_(SSL)(λ) is a spectral power distribution of thelight measured at the position of the objects is represented by

$\begin{matrix}{\lbrack {{Expression}\mspace{14mu} 69} \rbrack{{{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}\;{\phi_{SSL}{N(\lambda)}}}},}} & \;\end{matrix}$

all the φ_(SSL)N(λ) (N is 1 to M) can satisfy the <1>, <2> and <3>.

[1-33]

The illumination method according to [1-31] or [1-32], wherein

at least one light-emitting area of the M number of light-emitting areasis electrically driven independently from other light-emitting areas forperforming the illumination.

[1-34]

The illumination method according to [1-33], wherein

all the M number of light-emitting areas are electrically drivenindependently from other light-emitting areas.

[1-35]

The illumination method according to any one of [1-31] to [1-34],wherein

at least one selected from the group consisting of an average saturationdifference represented by the formula (3),

[Expression   70]$\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[1-36]

The illumination method according to [1-35], wherein

the luminance in the object is independently controlled when at leastone selected from the group of an average saturation differencerepresented by the formula (3),

 [Expression   71]$\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[1-37]

The illumination method according to [1-36], wherein

the luminance in the object is unchangeable when at least one selectedfrom the group of an average saturation difference represented by theformula (3),

[Expression   72]$\frac{\sum\limits_{n = 1}^{15}\;{\Delta\; C_{n}}}{15},$the correlated color temperature T_(SSL)(K), and the distance D_(uvSSL)from the black-body radiation locus is changed.[1-38]

The illumination method according to [1-36], wherein

the luminance in the object is decreased when the average saturationdifference represented by the formula (3),

[Expression  73] $\frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}$is increased.[1-39]

The illumination method according to [1-36], wherein

the illuminance in the object is increased when the correlated colortemplate T_(SSL)(K) is increased.

[1-40]

The illumination method according to [1-36], wherein

the luminance in the object is decreased when the distance D_(uvSSL)from the black-body radiation locus is decreased.

[1-41]

The illumination method according to any one of [1-31] to [1-40],wherein

if a maximum distance between two arbitrary points on a virtual outerperiphery enveloping the entire light-emitting areas closest to eachother is denoted by L, and a distance between the light-emitting deviceand the illumination object is denoted by H,

the distance H is set so as to satisfy5×L≦H≦500×L.[2-1]

A light-emitting device incorporating a light-emitting element includinga semiconductor light-emitting element, and a control element, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the light-emitting element in a main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the light-emitting device in the main radiantdirection is denoted by φ_(SSL)(λ)

Φ_(elm)(λ) does not satisfy at least one of the following Condition 1and Condition 2, and φ_(SSL)(λ) satisfies both the following Condition 1and Condition 2:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), and tristimulus values of the reference light that is selected according to T(K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 74]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 75]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[2-2]

The light-emitting device according to [2-1], wherein

Φ_(elm)(λ) does not satisfy at least one of the following Condition 3and Condition 4, and φ_(SSL)(λ) satisfies both the following Condition 3and Condition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 76} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 77} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

[2-3]

A light-emitting device incorporating a light-emitting element includinga semiconductor light-emitting element, and a control element, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the light-emitting element in a main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the light-emitting device in the main radiantdirection is denoted by φ_(SSL)(λ)

Φ_(elm)(λ) satisfies both of the following Condition 1 and Condition 2,and φ_(SSL)(λ) also satisfies both of the following Conditions 1 and 2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 78]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 79]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[2-4]

The light-emitting device according to [2-3], wherein

Φ_(elm)(λ) satisfies both of the following Condition 3 and Condition 4,and φ_(SSL)(λ) also satisfies both of the following Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 80} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 81} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

[2-5]

The light-emitting device according to [2-1] or [2-3], wherein

if D_(uv) derived from the spectral power distribution of the lightemitted from the light-emitting element in the main radiant direction isdenoted by D_(uv) (Φ_(elm)), and D_(uv) derived from the spectral powerdistribution of the light emitted from the light-emitting device in themain radiant direction is denoted by D_(uv) (φ_(SSL)), D_(uv)(φ_(SSL))<D_(uv) (Φ_(elm)) is satisfied.

[2-6]

The light-emitting device according to [2-1] or [2-3], wherein

if A_(cg) derived from the spectral power distribution of the lightemitted from the light-emitting element in the main radiant direction isdenoted by A_(cg) (φ_(elm)), and A_(cg) derived from the spectral powerdistribution of the light emitted from the light-emitting device in themain radiant direction is denoted by A_(cg) (φ_(SSL)), A_(cg)(Φ_(SSL))<A_(cg) (Φ_(elm)) is satisfied.

[2-7]

The light-emitting device according to [2-2] or [2-4], wherein

if an average of the saturation degree difference derived from thespectral power distribution of the light emitted from the light-emittingelement in the main radiant direction is denoted by SAT_(av) (Φ_(elm)),and

if an average of the saturation degree difference derived from thespectral power distribution of the light emitted from the light-emittingdevice in the main radiant direction is denoted by SAT_(av) (φ_(SSL)),

SAT_(av) (Φ_(elm))<SAT_(av) (φ_(SSL)) is satisfied.

[2-8] The light-emitting device according to any one of [2-1] to [2-7],wherein

the control element is an optical filter that absorbs or reflects lightin a range of 380 nm≦λ(nm)≦780 nm.

[2-9] The light-emitting device according to any one of [2-1] to [2-8],wherein

the control element has a collection function and/or a diffusionfunction of the light emitted from the light-emitting element.

[2-10]

The light-emitting device according to [2-9], wherein

the collection function and/or the diffusion function of the controlelement is implemented by at least one of the functions of a concavelens, a convex lens and a Fresnel lens.

[2-11]

The light-emitting device according to any one of [2-1] to [2-10],wherein

a luminous efficacy of radiation K (lm/W) in a wavelength range from 380nm to 780 nm as derived from the spectral power distribution φ_(SSL) (λ)of light emitted from the light-emitting device in the radiant directionsatisfies180(lm/W)≦K(lm/W)≦320(lm/W).[2-12]

The light-emitting device according to [2-2] or [2-4], wherein

the absolute value of each difference in hue angles |Δh_(n)|light-emitting device satisfies

0.0003≦|Δh_(n)|8.3 (degree) (where n is a natural number from 1 to 15).

[2-13]

The light-emitting device according to [2-2] or [2-4], wherein

the average SAT_(av) of the saturation difference of the light-emittingdevice represented by the Formula (3) satisfies the following Formula(4)′

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 82} \rbrack & \; \\{1.2 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq {6.3.}} & (4)\end{matrix}$[2-14]

The light-emitting device according to [2-2] or [2-4], wherein

the each saturation difference AC, of the light-emitting devicesatisfies

−3.4≦ΔC_(n)≦16.8 (where n is a natural number from 1 to 15).

[2-15]

The light-emitting device according to [2-2] or [2-4], wherein

the difference |ΔC_(max)−ΔC_(min)| between the maximum saturationdifference value of the light-emitting device and the minimum saturationdifference value thereof, satisfies3.2≦|ΔC _(max) −ΔC _(min)|≦17.8.[2-16]

The light-emitting device according to any one of [2-1] to [2-15],wherein

the light emitted from the light-emitting device in the radiantdirection has the distance D_(uv) from the black-body radiation locusthat specifies−0.0250≦D _(uv)≦−0.0100.[2-17]

The light-emitting device according to any one of [2-1] to [2-16],wherein

the index A_(cg) of the light-emitting device represented by the Formula(1) or (2) satisfies−322≦A _(cg)≦−12.[2-18]

The light-emitting device according to any one of [2-1] to [2-17],wherein

the luminous efficacy of radiation K (lm/W) in a wavelength range from380 nm to 780 nm as derived from the spectral power distribution φ_(SSL)(λ) of light emitted from the light-emitting device in the radiantdirection satisfies206(lm/W)≦K(lm/W)≦288(lm/W).[2-19]

The light-emitting device according to any one of [2-1] to [2-18],wherein

the correlated color temperature T(K) of the light-emitting devicesatisfies2550(K)≦T(K)≦5650(K).[2-20]

The light-emitting device according to any one of [2-1] to [2-19],wherein

illuminance at which the light emitted from the light-emitting device inthe radiant direction illuminates objects is 150 lx to 5000 lx.

[2-21]

The light-emitting device according to any one of [2-1] to [2-20],wherein

the light-emitting device emits, in the radiant direction, light emittedfrom one to six light-emitting elements.

[2-22]

The light-emitting device according to any one of [2-1] to [2-21],wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 380 nm or longer and shorter than 495 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 45 nm.

[2-23]

The light-emitting device according to [2-22], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 395 nm or longer and shorter than 420 nm.

[2-24]

The light-emitting device according to [2-22], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 420 nm or longer and shorter than 455 nm.

[2-25]

The light-emitting device according to [2-22], wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 455 nm or longer and shorter than 485 nm.

[2-26]

The light-emitting device according to any one of [2-1] to [2-21],wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 495 nm or longer and shorter than 590 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 75 nm.

[2-27]

The light-emitting device according to any one of [2-1] to [2-21],wherein

the peak wavelength of the emission spectrum of the semiconductorlight-emitting element is 590 nm or longer and shorter than 780 nm andthe full-width at half-maximum of the emission spectrum of thesemiconductor light-emitting element is 2 nm to 30 nm.

[2-28]

The light-emitting device according to any one of [2-1] to [2-21],wherein

the semiconductor light-emitting element is fabricated on any substrateselected from the group consisting of a sapphire substrate, a GaNsubstrate, a GaAs substrate and a GaP substrate.

[2-29]

The light-emitting device according to any one of [2-1] to [2-21],wherein

the semiconductor light-emitting element is fabricated on a GaNsubstrate or a GaP substrate and a thickness of the substrate is 100 μmto 2 mm.

[2-30]

The light-emitting device according to any one of [2-1] to [2-22],wherein

the semiconductor light-emitting element is fabricated on a sapphiresubstrate or a GaAs substrate and the semiconductor light-emittingelement is removed from the substrate.

[2-31]

The light-emitting device according to any one of [2-1] to [2-25],comprising a phosphor as a light-emitting element.

[2-32]

The light-emitting device according to [2-31], wherein

the phosphor includes one to five types of phosphors each havingdifferent emission spectra.

[2-33]

The light-emitting device according to [2-31] or [2-32], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 380 nmor longer and shorter than 495 nm and a full-width at half-maximum of 2nm to 90 nm.

[2-34]

The light-emitting device according to [2-33], wherein

the phosphor includes one or more types of phosphors selected from thegroup consisting of a phosphor represented by general formula (5) below,a phosphor represented by general formula (5)′ below, (Sr,Ba)₃MgSi₂O₈:Eu²⁺, and (Ba, Sr, Ca, Mg)Si₂O₂N₂:Eu(Ba,Sr,Ca)MgAl₁₀O₁₇:Mn,Eu  (5)Sr_(a)Ba_(b)Eu_(x)(PO₄)_(c)X_(d)  (5)′(in the general formula (5)′, X is Cl, in addition, c, d, and x arenumbers satisfying 2.7≦c≦3.3, 0.9≦d≦1.1, and 0.3≦x≦1.2, moreover, a andb satisfy conditions represented by a+b=5−x and 0≦b/(a+b)≦0.6).[2-35]

The light-emitting device according to [2-31] or [2-32], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 495 nmor longer and shorter than 590 nm and a full-width at half-maximum of 2to 130 nm.

[2-36]

The light-emitting device according to [2-35], wherein

the phosphor includes one or more types of phosphors selected from thegroup consisting of Si_(6−z)Al_(z)O_(z)N_(8−z):Eu (where 0<z<4.2), aphosphor represented by general formula (6) below, a phosphorrepresented by general formula (6)′ below, and SrGaS₄:Eu²⁺Ba_(a)Ca_(b)Sr_(c)Mg_(d)Eu_(x)SiO₄  (6)(in the general formula (6), a, b, c, d, and x satisfy a+b+c+d+x=2,1.0≦a≦2.0, 0≦b<0.2, 0.2≦c≦1.0, 0≦d<0.2, and 0<x≦0.5).Ba_(1−x−y)Sr_(x)Eu_(y)Mg_(1−z)Mn_(z)Al₁₀O₁₇  (6)(in the general formula (6)′, x, y, and z respectively satisfy0.1≦x≦0.4, 0.25≦y≦0.6, and 0.05≦z≦0.5).[2-37]

The light-emitting device according to [2-31] or [2-32], wherein

the phosphor includes a phosphor having an individual emission spectrum,when photoexcited at room temperature, with a peak wavelength of 590 nmor longer and shorter than 780 nm and a full-width at half-maximum of 2nm to 130 nm.

[2-38]

The light-emitting device according to [2-37], wherein

the phosphor includes one or more types of phosphors selected from thegroup consisting of a phosphor represented by general formula (7) below,a phosphor represented by general formula (7)′ below, (Sr, Ca,Ba)₂Al_(x)Si_(5−x)O_(x)N_(8−x):Eu (where 0≦x≦2), Eu_(y)(Sr, Ca,Ba)_(1−y):Al_(1+x)Si_(4−x)O_(x)N_(7−x) (where 0≦x<4, 0≦y<0.2),K₂SiF₆:Mn⁴⁺, A_(2+x)M_(y)Mn_(z)F_(n) (where A is Na and/or K; M is Siand Al; −1≦x≦1 and 0.9≦y+z≦1.1 and 0.001≦z≦0.4 and 5≦n≦7), (Ca, Sr, Ba,Mg)AlSiN₃:Eu and/or (Ca, Sr, Ba)AlSiN₃:Eu, and(CaAlSiN₃)_(1−x)(Si₂N₂O)_(x):Eu (where x satisfies 0<x<0.5)(La_(1−x−y)Eu_(x)Ln_(y))₂O₂S  (7)(in the general formula (7), x and y denote numbers respectivelysatisfying 0.02≦x≦0.50 and 0≦y≦0.50, and Ln denotes at least onetrivalent rare-earth element among Y, Gd, Lu, Sc, Sm, and Er)(k−x)MgO.xAF₂.GeO₂ :yMn⁴⁺  (7)′(in the general formula (7)′, k, x, and y denote numbers respectivelysatisfying 2.8≦k≦5, 0.1≦x≦0.7, and 0.005≦y≦0.015, and A is calcium (Ca),strontium (Sr), barium (Ba), zinc (Zn), or a mixture consisting of theseelements).[2-39]

The light-emitting device according to any one of [2-1] to [2-21],further comprising a phosphor as the light-emitting element, wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 395 nm or longer and shorter than 420 nm, andthe phosphor includes SBCA, β-SiAlON, and CASON.

[2-40]

The light-emitting device according to any one of [2-1] to [2-21],further comprising a phosphor as the light-emitting element, wherein

a peak wavelength of an emission spectrum of the semiconductorlight-emitting element is 395 nm or longer and shorter than 420 nm, andthe phosphor includes SCA, β-SiAlON, and CASON.

[2-41]

The light-emitting device according to any one of [2-1] to [2-40], whichis selected from the group consisting of a packaged LED, an LED module,an LED lighting fixture, and an LED lighting system.

[2-42]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as a residential uses' device.

[2-43]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as an exhibition illumination device.

[2-44]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as a presentation illumination device.

[2-45]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as a medical illumination device.

[2-46]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as a work illumination device.

[2-47]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as an illumination device incorporated in industrial equipments.

[2-48]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as an illumination device for interior of transportation.

[2-49]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as an illumination device for works of art.

[2-50]

The light-emitting device according to any one of [2-1] to [2-41], whichis used as an illumination device for aged persons.

[2-51]

A method for producing a light-emitting device: incorporating alight-emitting element which includes a semiconductor light-emittingelement; and a control element, the method comprising:

a step of preparing a first light-emitting device having thelight-emitting element; and

a step of producing a second light-emitting device by disposing thecontrol element so as to act on at least a part of light emitted fromthe first light-emitting device in a main radiant direction, wherein

if a wavelength is denoted by λ(nm), a spectral power distribution of alight emitted from the first light-emitting device in the main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the second light-emitting device in the mainradiant direction is denoted by φ_(SSL)(λ)

Φ_(elm)(λ) does not satisfy at least one of the following Condition 1and Condition 2, and φ_(SSL)(λ) satisfies both the Condition 1 andCondition 2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)), and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(X), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 83]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 84]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[2-52]

The method for producing a light-emitting device according to [2-51],wherein

Φ_(elm)(λ) does not satisfy at least one of the following Condition 3and Condition 4, and φ_(SSL)(λ) satisfies both the Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 85} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 86} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|<19.6,where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(nSSL)−θ_(nref).

[2-53]

A method for producing a light-emitting device incorporating: alight-emitting element which includes a semiconductor light-emittingelement; and a control element, the method comprising:

a step of preparing a first light-emitting device having thelight-emitting element; and

a step of producing a second light-emitting device by disposing thecontrol element so as to act on at least a part of light emitted fromthe first light-emitting device in a main radiant direction, wherein

if a wavelength is denoted by λ (nm), a spectral power distribution of alight emitted from the first light-emitting device in the main radiantdirection is denoted by Φ_(elm)(λ), and a spectral power distribution ofa light emitted from the second light-emitting device in the mainradiant direction is denoted by φ_(SSL)(λ),

Φ_(elm)(λ) satisfies both the following Condition 1 and Condition 2, andφ_(SSL)(λ) also satisfies both the following Condition 1 and Condition2:

Condition 1:

a light, of which distance D_(uv) from a black-body radiation locus asdefined by ANSI C78.377 in a spectral power distribution of the targetlight satisfies −0.0350≦D_(uv)−0.0040, is included;

Condition 2:

if a spectral power distribution of the target light is denoted by φ(λ),a spectral power distribution of a reference light that is selectedaccording to T (K) of the target light is denoted by φ_(ref) (λ),tristimulus values of the target light are denoted by (X, Y, Z), andtristimulus values of the reference light that is selected according toT (K) of the light emitted from the light-emitting device in the radiantdirection are denoted by (X_(ref), Y_(ref), Z_(ref)) and

if a normalized spectral power distribution S (λ) of target light, anormalized spectral power distribution S_(ref) (λ) of a reference light,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS(λ)=φ(λ)/YS _(ref)(λ)=φ_(ref)(λ)/Y _(ref)ΔS(λ)=S _(ref)(λ)−S(λ), and

when a wavelength that produces a longest wavelength local maximum valueof S(λ) in a wavelength range from 380 nm to 780 nm is denoted by λ_(R)(nm),

an index A_(cg) represented by the following Formula (1) satisfies−360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2exists in the longer wavelength-side of λ_(R), and

an index A_(cg) represented by the following Formula (2) satisfies360≦A_(cg)≦−10, in the case when the wavelength Λ4 that is S(λ_(R))/2does not exist in the longer wavelength-side of λ_(R),[Expression 87]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)[Expression 88]A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2).[2-54]

The method for producing a light-emitting device according to [2-53],wherein

Φ_(elm)(λ) satisfies both of the following Condition 3 and Condition 4,and φ_(SSL)(λ) also satisfies both of the following Condition 3 andCondition 4:

Condition 3:

if an a* value and a b* value in CIE 1976 L*a*b* color space of 15Munsell renotation color samples from #01 to #15 listed below whenmathematically assuming illumination by the target light arerespectively denoted by a*_(n) and b*_(n) (where n is a natural numberfrom 1 to 15), and

if an a* value and a b* value in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by a reference light that is selected according to acorrelated color temperature T (K) of the light emitted in the radiantdirection are respectively denoted by a*_(nref) and b*_(nref) (where nis a natural number from 1 to 15), then each saturation differenceΔC_(n) satisfies

−3.8≦ΔC_(n)≦18.6 (where n is a natural number from 1 to 15), and

an average SAT_(av) of saturation difference represented by formula (3)below satisfies formula (4) below and

$\begin{matrix}\lbrack {{Expression}\mspace{14mu} 89} \rbrack & \; \\{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\\lbrack {{Expression}\mspace{14mu} 90} \rbrack & \; \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$

if a maximum saturation difference value is denoted by ΔC_(max) and aminimum saturation difference value is denoted by ΔC_(min), then adifference |ΔC_(max)−ΔC_(min)| between the maximum saturation differencevalue and the minimum saturation difference value satisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6.

where ΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²}

with the 15 Munsell renotation color samples being:

#01 7.5P 4/10 #02 10PB 4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #062.5BG 6/10 #07 2.5G 6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #1110YR 7/12 #12 5YR 7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12Condition 4:

if hue angles in CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination bythe target light are denoted by θ_(n) (degrees) (where n is a naturalnumber from 1 to 15), and

if hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T (K) of the light emitted in the radiant direction aredenoted by θ_(nref) (degrees) (where n is a natural number from 1 to15), then an absolute value of each difference in hue angles |Δh_(n)|satisfies

0≦|Δh_(n)|≦9.0 (degree) (where n is a natural number from 1 to 15),

where Δh_(n)=θ_(n)−θ_(nref).

EXPLANATION OF REFERENCE NUMERALS

-   100 light emitting device-   1 light emitting area 1-   11 light emitting area 1-1-   12 light emitting area 1-2-   13 light emitting area 1-3-   2 light emitting area 2-   21 light emitting area 2-1-   22 light emitting area 2-2-   23 light emitting area 2-3-   3 light emitting area 3-   31 light emitting area 3-1-   32 light emitting area 3-2-   4 light emitting area 4-   5 light emitting area 5-   6 semiconductor light-emitting element-   7 virtual outer periphery-   71 two points on virtual outer periphery-   72 distance between two points on virtual outer periphery-   10 packaged LED-   20 packaged LED-   25 packaged LED-   30 illumination system-   301 LED bulb (light emitting area 1)-   302 LED bulb (light emitting area 2)-   303 ceiling-   40 pair of packaged LEDs-   400 packaged LED-   401 light emitting area 1-   402 light emitting area 2-   51 housing-   52 LED chip-   52 a blue LED chip-   52 b green LED chip-   52 c red LED chip-   52 d thermal radiation filament-   53 package-   54 phosphor-   55 cut-off filter (control element)-   56 Encapsulant layer-   510 packaged LED (light-emitting device having low level processing)-   511 incandescent bulb (light-emitting device having mid-level    processing)-   520 LED light bulb with filter (light-emitting device having high    level processing)-   530 lighting system (light-emitting device having further high level    processing)

INDUSTRIAL APPLICABILITY

The light-emitting device such as an illumination light source, alighting fixture, a lighting system, and the like, the method fordesigning the light-emitting device, the method for driving thelight-emitting device and the illumination method according to the firstto fourth inventions of the present invention has an extremely widefield of application and may be used without being limited to particularuses. However, in consideration of the features of The light-emittingdevice such as an illumination light source, a lighting fixture, alighting system, and the like, the method for designing thelight-emitting device, the method for driving the light-emitting deviceand the illumination method according to the first to fourth inventionsof the present invention, the illumination method or the light-emittingdevice according to the present invention is favorably applied to thefollowing fields.

For example, when illuminated by the light-emitting device or theillumination method according to the first or the fourth invention ofthe present invention, white may be perceived as being whiter, morenatural, and more comfortable as compared to a conventional aconventional light-emitting device or illumination method even at asimilar CCT and a similar illuminance. Furthermore, differences inlightness among achromatic colors such as white, gray, and black becomemore visible.

As a result, for example, black letters or the like on an ordinary sheetof white paper become more legible. To utilize such features, favorableapplications include a reading light, lighting for a writing desk, andwork lighting such as office lighting. In addition, while work mayconceivably involve performing a visual external examination of fineparts, distinguishing between near colors of cloth or the like, checkingcolor in order to verify freshness of meat, performing a productinspection by comparing with a criteria sample, and the like at afactory or the like, illumination by the illumination method accordingto the fourth invention of the present invention makes coloridentification among close hues easier and realizes a work environmentthat is as comfortable as though in a high-illuminance environment. Evenfrom such a perspective, applications to work lighting are favorable.

Furthermore, since color discrimination ability increases, for example,applications to medical lighting such as a light source for surgicaloperations and a light source used in a gastroscope or the like are alsofavorable. While arterial blood is vivid red due to its high oxygencontent, venous blood is dark red due to its high carbon dioxidecontent. Although arterial blood and venous blood are both red, chromasof the colors differ from each other. Therefore, with the illuminationmethod or device according to the fourth or first invention of thepresent invention which achieves favorable color appearance (chroma), itis expected that arterial blood and venous blood can be readilydistinguished from each other. In addition, since it is obvious thatfavorable color representation in color image information such as anendoscope has a significant effect on diagnosis, it is expected that anormal location and a lesion location can be readily distinguished fromeach other. Due to similar reasons, the illumination method can befavorably applied to an illumination method used in industrialequipments such as a product image judgment device.

When illuminated by the light-emitting device or the illumination methodaccording to the first or fourth invention of the present invention, atruly natural color appearance as though viewed under several tens ofthousands of lx such as outdoor illuminance on a sunny day is achievedfor a majority of, and in some cases, all colors such as purple, bluishpurple, blue, greenish blue, green, yellowish green, yellow, reddishyellow, red, and reddish purple even when illuminance only ranges fromaround several thousand lx to several hundred lx. In addition, the skincolor of the subjects (Japanese), various foods, clothing, wood colors,and the like which have intermediate chroma also acquire natural colorappearances which many of the subjects feel more favorable.

Therefore, by applying the light-emitting device or the illuminationmethod according to the first or fourth invention of the presentinvention to ordinary lighting for homes and the like, it is conceivablethat food may appear fresher and more appetizing, newspapers, magazines,and the like may become more legible, and visibility of differences inlevel in the house may increase, thereby contributing to improving homesafety. Accordingly, the first to fifth inventions of the presentinvention are favorably applied to home lighting. In addition, thepresent invention is also favorable as exhibit lighting for clothing,food, vehicles, suitcases, shoes, ornaments, furniture, and the like,and enables lighting which makes such items standout from theirsurroundings.

The present invention is also favorable as lighting for goods such ascosmetics in which slight differences in color are the decisive factorwhen purchasing the goods. When used as exhibit lighting for whitedresses and the like, since subtle differences in color become morevisible such as a difference between bluish white and creamy white amongsimilar whites, a person can select a color that is exactly according tohis or her desire. Furthermore, the present invention is also favorableas presentation lighting at a wedding center, a theater, and the like,and enables a pure white dress or the like to be perceived as being purewhite and kimonos, makeup, in kabuki or the like to appear vividly. Thepresent invention also favorably highlights skin tones. In addition, byusing the present invention as lighting in a hair salon, colors that areno different than those perceived outdoors can be obtained during haircoloring and excessive dyeing or insufficient dyeing can be prevented.

Particularly in the light-emitting device or the illumination methodaccording to the second embodiment of the first or fourth invention ofthe present invention, a relative spectral intensity of light havingrelatively high energy wavelength components, such as ultraviolet, nearultraviolet, purple or indigo, from the light-emitting element isreduced using the control element, hence fading, degeneration,corrosion, deterioration or the like of the illumination object, such asclothes and food, can be decreased. Further, in the light-emittingdevice or the illumination method according to the second embodiment ofthe first or fourth invention of the present invention, relativespectral intensity of light having wavelength components that couldcause thermal irradiation from the light-emitting element, such as nearultraviolet, middle infrared and far infrared, is decreased, hencedegeneration, corrosion, deterioration or the like such as food can bedecreased.

Furthermore, since white appears more white, achromatic colors can bereadily distinguished, and chromatic colors attain their naturalvividness, the first to fifth inventions of the present invention arealso favorable as a light source in a location where a wide variety ofactivities are conducted in a given limited space. For example,passengers in an airplane read, work, and eat at their seats. Similarsituations take place on a train, a long-distance bus, and the like. Thefirst to fifth inventions of the present invention is favorablyapplicable as interior lighting in such public transport.

In addition, since white appears more white, achromatic colors can bereadily distinguished, and chromatic colors attain their naturalvividness, the first to fifth inventions of the present inventionenables paintings and the like in an art museum or the like to beilluminated in a natural tone as though viewed outdoors and is thereforealso favorable as lighting for works of art.

On the other hand, the first to fifth inventions of the presentinvention is also favorably applicable as lighting for aged persons. Inother words, even in case where small characters are hard to read anddifference in steps or the like are hard to see under normalilluminance, by applying the illumination method or the light-emittingdevice according to the fourth or first invention of the presentinvention, such problems can be solved since achromatic colors andchromatic colors can be readily distinguished from one another.Therefore, the present invention is also favorably applicable tolighting in public facilities or the like which are used by the generalpublic such as a waiting room in a retirement house or a hospital, abook store, and a library.

Furthermore, the illumination method or the light-emitting deviceaccording to the present invention can be favorably used in applicationsfor securing visibility by adapting to an illumination environment inwhich illuminance is often at a relatively low level due to variouscircumstances.

For example, the illumination method or the light-emitting deviceaccording to the present invention is favorably applied to street lamps,head lights of vehicles, and foot lamps to increase visibility ascompared to using conventional light sources.

The present invention has been described in detail with reference to thepreferred embodiment thereof, but numerous modifications and variationscan be made by those skilled in the art, which are included in thespirit and scope of the present invention described in the Claims.

The invention claimed is:
 1. A light-emitting device comprising alight-emitting element and satisfying the following A or B: A: thelight-emitting device comprises M number of light emitting areas, whereM is 2 or greater natural number, and has the light-emitting elements inthe light emitting areas, wherein when φ_(SSL)N(λ), with N being 1 to M,is a spectral power distribution of a light emitted from each lightemitting area in a main radiant direction of the light-emitting device,φ_(SSL)(λ), which is a spectral power distribution of all the lightsemitted from the light-emitting device in the radiant direction, is${{\phi_{SSL}(\lambda)} = {\sum\limits_{N = 1}^{M}{\phi_{SSL}{N(\lambda)}}}},$wherein φ_(SSL)(λ) emitted from the light-emitting device satisfies boththe following Condition 1 and Condition 2; or B: the light-emittingdevice comprises the light-emitting element and a control element,wherein if a wavelength is denoted by λ(nm), a spectral powerdistribution of a light emitted from the light-emitting element in amain radiant direction is denoted by Φ_(elm)(λ), and a spectral powerdistribution of a light emitted from the light-emitting device in themain radiant direction is denoted by φ_(SSL)(λ), wherein Φ_(elm)(λ) doesnot satisfy at least one of the following Conditions 1 and 2: Condition1: light emitted from the light-emitting device includes, in the mainradiant direction thereof, light whose distance D_(uvSSL) from ablack-body radiation locus as defined by ANSI C78.377 satisfies−0.0350≦D_(uvSSL)≦−0.0040, Condition 2: if a spectral power distributionof light emitted from the light-emitting device in the radiant directionis denoted by φ_(SSL) (λ), a spectral power distribution of a referencelight that is selected according to T_(SSL) (K) of the light emittedfrom the light-emitting device in the radiant direction is denoted byφ_(ref) (λ), tristimulus values of the light emitted from thelight-emitting device in the radiant direction are denoted by (X_(SSL),Y_(SSL), Z_(SSL)), and tristimulus values of the reference light that isselected according to T_(SSL) (K) of the light emitted from thelight-emitting device in the radiant direction are denoted by (X_(ref),Y_(ref), Z_(ref)), and if a normalized spectral power distributionS_(SSL) (λ) of light emitted from the light-emitting device in theradiant direction, a normalized spectral power distribution S_(ref) (λ)of a reference light that is selected according to T_(SSL) (K) of thelight emitted from the light-emitting device in the radiant direction,and a difference ΔS (λ) between these normalized spectral powerdistributions are respectively defined asS _(SSL)(λ)=φ_(SSL)(λ)/Y _(SSL),S _(ref)(λ)=φ_(ref)(λ)/Y _(ref)andΔS(λ)=S _(ref)(λ)−S _(SSL)(λ) and an index A_(cg) represented by thefollowing Formula (1) satisfies −360≦A_(cg)≦−10, in the case when awavelength that produces a longest wavelength local maximum value ofS_(SSL) (λ) in a wavelength range from 380 nm to 780 nm is denoted byλ_(R) (nm), and a wavelength Λ4 that assumes S_(SSL) (λ_(R))/2 exists ona longer wavelength-side of λ_(R), and an index A_(cg) represented bythe following Formula (2) satisfies −360≦A_(cg)≦−10, in the case when awavelength that produces a longest wavelength local maximum value ofS_(SSL) (λ) in a wavelength range from 380 nm to 780 nm is denoted byλ_(R) (nm), and a wavelength Λ4 that assumes S_(SSL) (λ_(R))/2 does notexist on a longer wavelength-side of λ_(R),A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ^(Λ4) ΔS(λ)dλ  (1)A _(cg)=∫₃₈₀ ⁴⁹⁵ ΔS(λ)dλ+∫ ₄₉₅ ⁵⁹⁰(−ΔS(λ))dλ+∫ ₅₉₀ ⁷⁸⁰ ΔS(λ)dλ  (2). 2.The light-emitting device according to claim 1, satisfying the A.
 3. Thelight-emitting device according to claim 2, wherein a semiconductorlight-emitting element is included in at least one of the light emittingareas as the light-emitting element.
 4. The light-emitting deviceaccording to claim 2, including light emitting areas so that φ_(SSL)(λ)can satisfy the Conditions 1 and 2 by changing a luminous flux amountand/or a radiant flux amount emitted from the light emitting areas. 5.The light-emitting device according to claim 2, wherein all of theφ_(SSL)N(λ), with N being 1 to M, satisfies the Condition 1 andCondition
 2. 6. The light-emitting device according to claim 2, whereinat least one light emitting area of the M number of light emitting areashas wiring that allows the light emitting area to be electrically drivenindependently from other light emitting areas.
 7. The light-emittingdevice according to claim 6, wherein all the M numbers of light emittingareas each have wiring that allows the light emitting area to beelectrically driven independently from other light emitting areas. 8.The light-emitting device according to claim 2, wherein at least oneselected from the group consisting of the index A_(cg) represented bythe Formula (1) or (2), the correlated color temperature T_(SSL)(K) andthe distance D_(uvSSL) from the black-body radiation locus can bechanged.
 9. The light-emitting device according to claim 8, wherein aluminous flux and/or a radiant flux emitted from the light-emittingdevice in the main radiant direction can be independently controlledwhen at least one selected from the group consisting of the index A_(cg)represented by the Formula (1) or (2), the correlated color temperatureT_(SSL)(K) and the distance D_(uvSSL) from the black-body radiationlocus is changed.
 10. The light-emitting device according to claim 2,wherein a maximum distance L between two arbitrary points on a virtualouter periphery enveloping the entire light emitting areas closest toeach other, is 0.4 mm or more and 200 mm or less.
 11. The light-emittingdevice according to claim 2, comprising the light emitting areas thatallow φ_(SSL)(λ) to further satisfy the following Conditions 3 to 4 bychanging a luminous flux amount and/or a radiant flux amount emittedfrom the light emitting areas: Condition 3: if an a* value and a b*value in CIE 1976 L*a*b* color space of 15 Munsell renotation colorsamples from #01 to #15 listed below when mathematically assumingillumination by the light emitted in the radiant direction arerespectively denoted by a*_(nSSL) and b*_(nSSL), where n is a naturalnumber from 1 to 15, and if an a* value and a b* value in CIE 1976L*a*b* color space of the 15 Munsell renotation color samples whenmathematically assuming illumination by a reference light that isselected according to a correlated color temperature T_(SSL) (K) of thelight emitted in the radiant direction are respectively denoted bya*_(nref) and b*_(nref), where n is a natural number from 1 to 15, theneach saturation difference ΔC_(n) satisfies −3.8≦ΔC_(n)≦18.6, where n isa natural number from 1 to 15, and an average saturation differencerepresented by formula (3) below satisfies formula (4) below and$\begin{matrix}\frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} & (3) \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$ if a maximum saturation difference value is denoted byΔC_(max) and a minimum saturation difference value is denoted byΔC_(min), then a difference |ΔC_(max)−ΔC_(min)| between the maximumsaturation difference value and the minimum saturation difference valuesatisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6, whereΔC_(n)=√{(a*_(nSSL))²+(b*_(nSSL))²}−√{(a*_(nref))²+(b*_(nref))²} withthe 15 Munsell renotation color samples being: #01 7.5P 4/10 #02 10PB4/10 #03 5PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #06 2.5BG 6/10 #07 2.5G6/12 #08 7.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #11 10YR 7/12 #12 5YR7/12 #13 10R 6/12 #14 5R 4/14 #15 7.5RP 4/12

Condition 4: if hue angles in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by the light emitted in the radiant direction are denotedby θ_(nSSL), in degrees, where n is a natural number from 1 to 15, andif hue angles in a CIE 1976 L*a*b* color space of the 15 Munsellrenotation color samples when mathematically assuming illumination by areference light that is selected according to the correlated colortemperature T_(SSL) (K) of the light emitted in the radiant directionare denoted by θ_(nref), in degrees, where n is a natural number from 1to 15, then an absolute value of each difference in hue angles |Δh_(n)|satisfies 0≦|Δh_(n)|≦9.0 degree, where n is a natural number from 1 to15, where Δh_(n)=θ_(nSSL)−θ_(nref).
 12. The light-emitting deviceaccording to claim 2, wherein a luminous efficacy of radiation K (lm/W)in a wavelength range from 380 nm to 780 nm as derived from the spectralpower distribution φ_(SSL) (λ) of light emitted from the light-emittingdevice in the radiant direction satisfies180(lm/W)≦K(lm/W)≦320(lm/W).
 13. The light-emitting device according toclaim 2, wherein a correlated color temperature T_(SSL) (K) of lightemitted from the light-emitting device in the radiant directionsatisfies2550(K)≦T _(SSL)(K)≦5650(K).
 14. The light-emitting device according toclaim 1, satisfying the B.
 15. The light-emitting device according toclaim 14, wherein the light-emitting element includes a semiconductorlight-emitting element.
 16. The light-emitting device according to claim14, wherein Φ_(elm)(λ) does not satisfy at least one of the followingCondition 3 and Condition 4, and φ_(SSL)(λ) satisfies both the followingCondition 3 and Condition 4: Condition 3: if an a* value and a b* valuein CIE 1976 L*a*b* color space of 15 Munsell renotation color samplesfrom #01 to #15 listed below when mathematically assuming illuminationby the target light are respectively denoted by a*_(n) and b*_(n), wheren is a natural number from 1 to 15, and if an a* value and a b* value inCIE 1976 L*a*b* color space of the 15 Munsell renotation color sampleswhen mathematically assuming illumination by a reference light that isselected according to a correlated color temperature T (K) of the lightemitted in the radiant direction are respectively denoted by a*_(nref)and b*_(nref), where n is a natural number from 1 to 15, then eachsaturation difference ΔC_(n) satisfies −3.8≦ΔC_(n)≦18.6, where n is anatural number from 1 to 15, and an average SAT_(av) of saturationdifference represented by formula (3) below satisfies formula (4) belowand $\begin{matrix}{{SAT}_{av} = \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15}} & (3) \\{{1.0 \leqq \frac{\sum\limits_{n = 1}^{15}{\Delta\; C_{n}}}{15} \leqq 7.0},} & (4)\end{matrix}$ if a maximum saturation difference value is denoted byΔC_(max) and a minimum saturation difference value is denoted byΔC_(min) then a difference |ΔC_(max)−ΔC_(min)| between the maximumsaturation difference value and the minimum saturation difference valuesatisfies2.8≦|ΔC _(max) −ΔC _(min)|≦19.6, whereΔC_(n)=√{(a*_(n))²+(b*_(n))²}−√{(a*_(nref))²+(b*_(nref))²} with the 15Munsell renotation color samples being: #01 7.5P 4/10 #02 10PB 4/10 #035PB 4/12 #04 7.5B 5/10 #05 10BG 6/8 #06 2.5BG 6/10 #07 2.5G 6/12 #087.5GY 7/10 #09 2.5GY 8/10 #10 5Y 8.5/12 #11 10YR 7/12 #12 5YR 7/12 #1310R 6/12 #14 5R 4/14 #15 7.5RP 4/12

Condition 4: if hue angles in CIE 1976 L*a*b* color space of the 15Munsell renotation color samples when mathematically assumingillumination by the target light are denoted by θ_(n), in degrees, wheren is a natural number from 1 to 15, and if hue angles in a CIE 1976L*a*b* color space of the 15 Munsell renotation color samples whenmathematically assuming illumination by a reference light that isselected according to the correlated color temperature T (K) of thelight emitted in the radiant direction are denoted by θ_(nref), indegrees, where n is a natural number from 1 to 15, then an absolutevalue of each difference in hue angles |Δh_(n)| satisfies 0≦|Δh_(n)|≦9.0degree, where n is a natural number from 1 to 15, whereΔh_(n)=θ_(n)−θ_(nref).